It does not necessarily mean anything - he may not be interested in your smiling.
It means he's nice, don't look to into it.
act nice and smile.
He wants to have sex with you and "put a smile on your face."
It mean he is trying to let you know he likes you by complimenting you.
It means he's into you.
he has acknowledged your existence, good for you! (if you like him)
It means that he likes it.
Yes, i mean i'd think well if he's a nice guy.
He doesn't want you to see him smile? Are you sure he was actually holding back a smile? He doesn't want you to know how he feels...why???? that depends on who this guy is to you and many other factors.
it means a girl that shares his sense of humor
sometimes it depends on his personality i mean if u poke him and he smiles that might mean that its only a friend smile but if he likes u he'll smile and laugh