Thanks! I'm trying to be mindful of that, too - as in, I know this one map I'm "editing" is only for my personal use (It's this super old Unreal Deathmatch map I found of a city that's got plenty of awesome passageways/buildings, but can definitely be added onto... plus, the bot pathing was abysmal, so I figured since I like playing off-line plenty I would want to fix that as well, I can post pics when I'm done) so I'm trying NOT to fill it full of random pointless eyecandy that I know a) Won't add anything to the map, b) will DETRACT from the map by slowing it down, as it is a city map and is already pretty dense, c) will only be seen by me, and I don't really want the stuff anyhow.
I'm certainly not suffering from a lack of ideas, either. Which is good and bad, in a sense; good in that I see a portion of the map, and I already know what I would like to see in it, bad in that we all know the limitations of the glorious U1 engine, and if I really allowed myself to add everything I wanted to the darn map I'm afraid it would detract from the smoothness of gameplay/the node counts.
All in all, you're right though - it's always worth it in the end!
Random Edit Post-Script: What is this frustrating desire among the Unreal mappers of yester-year to integrate sketchy textures of a sexual nature into their work? I don't get it... I don't think I want to.