Least and favorite part of Portal 2 mapping?
We all love Portal and Portal 2, and many of us on this forum map for it as well, whether it's with PTI or Hammer. And I believe we can all agree that there are some things that you love about mapping, and a few things that utterly bore you about it, which typically leads to a traumatic case of endlessly-navigating-around-map-in-hammer-pressing-control-s-over-and-over syndrome. What is your favorite part of mapping, and what is your least favorite part of mapping?
Favorite: Detailing. I'm not very good at coming up with puzzle ideas and it can take quite a while for me to think of something, so I find detailing very relaxing. I can just put some music on and then rhythmically shift-drag square beams or clip walls.
Least favorite: Building the starting geometry. It's really uninspiring for me, since all I can imagine as I'm doing this is how the hell this is going to end up as a finished map. When you're starting, everything just looks like a bunch of blocky developer textures.
Favorite: scripting.
Least favorite: detailing. I'm not very good at it and can never get it to look right.
favorite: everything, exept...
least favorite: the once in a while where i have to divide a room with a wall, or i mess some small thing up with aligning things and the whole map is off as a result of that.
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Im blue, a Clean Christian Furry with Autism.
Favorite: Small details and lighting. Even though a lot of the details I try to put it wouldn't be noticed by an everyday player, and would inevitably just lower framerates, I still like the process. And getting the perfect light ambience for a room just makes me feel kinda fuzzy inside.
Least favorite: Getting delay times right. I hate it when sounds overlap, or that one prop animates just half a second too early. I find it nearly impossible to get that kinda thing perfect.
Plus, I kinda find all this white a little blinding.
Favorite: concept designing. I think of many cool ideas that I'd never have a use for in portal, but are just awesome all the same. Also, story concept developing is a big thing for me, thinking in my head how I'd manipulate voice lines using existing sound clips to make a story, working around portal 2 limits, and how to make it interesting.
Least Favorite: making interesting test chambers. I'd much rather get straight to the point of a map without the tutorial areas or useless chambers I already know how to do, but mainly because I'm not very good at making good ones. They come out too easy or pointless usually, and if I make them harder, they become next to impossible to solve because they are too confusing after solving unintendid solutions and fixing stuff. I am not very good at making maps that reuse testing elements more than a few times, and I find the default instances for things like elevators and global entities to be far too confusing, and would rather make my own without all the seemingly useless scripts and entities valve likes to put in there.
Aperture Science: We do our science asbestos we can!
I have a lot of favorite things, a particular one is simply making progress. I hate working and not seeing any change. I guess this leads into my 'above all else' favorite thing is looking back at a finished map. I guess it brings a certain sense of pride, knowing what you've made. Especially one you've worked on for a while. A close second is when things work. It's so satisfying when exactly what you want to happen, happens.
Least favorite, however, is troubleshooting. Mystery leaks, compile crashes, tweaking, lighting errors, bad I/O...ugh 
I suppose it's because it's the opposite of progress.
Favourite:
1. Well, what I enjoy the most is to achieve "non-common" things, to develop new cool effects or custom new stuff, trying to make a new experience for the player. I just love to customize every single detail to create a homogenic and creative atmosphere / environment. I'm really perseverant, and if I can think of something cool that I haven't really seen before, I won't stop until I achieve it. And when I do, that feeling of success is what keeps me hooked to mapping, apart from the map itself if I really achieved all the things I planned and I'm satisfied with the work.
2. In that process of doing the above, I've learnt many things directly related to mapping like some modelling, designing, some scripting or programming.... and as I learnt them, I started to love them all as well.
3. What to say about puzzles. I was hooked from the very first moment I played Portal in a way I didn't know it was possible. I LOVE all kind of puzzles and puzzle games, and as they are more challenging I love them even more. I love when I can think of cool mechanic or chain of them and I can isolate it from unintended moves to make a good Portal puzzle. I love thinking with portals and develop puzzles for this game.
Least Favourite:
Unexpected issues. I hate being stopped for too long by a little detail or whatever that I can't achieve. Sometimes that "detail" is not truly important in general, but I want it to be solved and I want it the way I want it... Maybe this is something I have to fix somehow in the depth of my mind in order to be able to admit a "softer" version (or substitute) of the first idea I made in my mind. However, I tend to solve it eventually, and along the way of doing it, I might have learnt something new becoming even better mapper... and that makes the issue turn into a good thing in the end 
useful tools and stuff here on TWP 
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Since I'm a PTI guy, I can't really pick a favorite now 
I do enjoy when I finally figure out how to make a big and complicated puzzle, however, since I'm not very clever.
Least favorite: My computer takes 10 minutes to compile a map. Don't even think about running hammer and P2 at the same time on it. Sad.
The original Portal game is where I started to get into 3D mapping and the Source engine. After 6 or so years of mapping for Portal, HL2, L4D, etc; I always go back to Portal/Portal like projects due to these reasons:
1) The map geometry is the most simplistic out of all Source, and perhaps most current games out there. You don't need to worry about advance detailing if you don't want to. This makes Portal/Portal 2 a much more welcoming game to start learning the source engine then HL2 or TF2.
Sure, in Portal 2 you can do the vegetation, destruction, and all that fancy stuff. But to make a basic Portal map, all you need is a few walls, a ceiling and a floor at the very least.
2) It's (mostly) a Single-Player experience that people enjoy and may go back to. I never saw a reason to map for HL2, or a desire to download custom HL2 maps. When people did HL2 themed stuff, it was usually a full mod. However, Portal is one of those games that beg for user generated maps. Even if you look at the X06 demo, the Portal UI has a slot for "CUSTOM MAPS" which turned into the "BONUS MAPS" section. Valve knew this would be a game that people would want to make maps for, and share with others.
You also don't need to worry about the stuff you would need to worry about in TF2/Counter-Strike/whatever, and worry about team spawns, weapon pickups, round times, etc. If you are doing co-op maps for Portal 2, the rules stay the same as if you were doing singleplayer. You would just need to think with another set of portals.
3) Again, the simplicity. Seriously, the simplicity of Portal is genius.
4) Ok, this does not apply to Portal 2 as much, but something that was kick-ass in Portal was that with just one map you can release a advance and challenges with the original map. It was one map, but you could be given two, and three sets of challenges to face. I was never good at setting these challenges, but the idea of having them there is what I really miss.
My least Favorite aspect is that you're map will never be for everyone. Sure, you can disagree with me here, but there are people who like complex puzzles that look like chaos at first glance, and other people like maps that they can play though fluently, and still have a ton of fun. Then you have the remaining people who like those fling puzzles you use to see in Portal 1 maps such as the side fling and crouch fling. (i.e Play Logic Portals. Especially 04.) Pretty much, just make type of portal maps you would want to play, cause in the end someone is gonna have a problem with it anyway.
The more you give, the less appreciated it will be received.