In my case, I didn't notice any signals my girlfriend was sending, or else ignored them thinking I was imagining them. It finally took my friends and her friends to hammer sense into me and go "hey look, dumbass, she likes you. NOTICE."
However, I always end up being the guy who everyone else turns to for "hey, does she like me?" because I'm good at noticing that for other people.
Ah, sweet sweet irony.
