"There are no ugly people - some people are just easier to look at."
This is an interesting topic and there are many "correct" answers.
I'm off to work soon (to study this topic a bit more
) so I only post "briefly".
Looks is certainly first impression thing, but I would also join the confidence band-wagon when speculating this further.
I have to say, to my shame, that similarly to the OP, I find chubby people less attractive to talk to. Chubbiness affects me more than looks, because I find human face very interesting. I'm very curious about people's expressions.
Sometimes I think that maybe this also may be reason, people are "attracted" to
you. If you show curiosity towards them in a positive way, they find it easier to approach and there's this confidence thing. But then again I've found some people avoiding too sharp look at them.
There's also one thing that affects me: how close this person is to my personal comfort zone. If they get too close physically or in some other way invade this territory of mine (stalking/observing), they might not be that welcome.