Even professional programmers can get that feeling when looking at some of the really popular apps/webapps/games. You have to keep in mind though that none of those are built by a single person but by at least a couple of people (usually dozens upon dozens). The key is to start small but to start somewhere and keep going.
Lately, I've been getting better at catching my "someone should build X" ideas. I used to quickly (and unconsciously) discard them instead of thinking that I could build them myself. Sometimes the ideas aren't even related to software but I'm still keeping them. Who knows, should I ever get tired of programming I may actually build up on them.