I dunno, the day I realized that something I was working on sounded like the soundtrack for a beer commercial I kinda wanted to ditch the whole concept. Unfortunaly, I can still remember the beer commercial sounding verse, and forgot the chorus which I really liked.

Anyway, I tend to write alot of ideas that sound like crap as just bass or just guitar, but sound really great as a band peice. I think every idea should be held onto, it can usually work in some context.