my money's on he likes you.
the part about him smiling.
He likes you, most likely.
i have this habit at work and when im on camera...i smile at everyone,it comes natural from me...i like to smile a lot.
not like staring at them ...but as i walk on the street sometimes i look at people eyes and i smile at them,but is not just random people they are people that i feel like smiling at them...and is never to try to have something with them,it is just a nice feeling smiling...and they always return the gesture...
He is in love with you.!
he is fantisizing about acts with you
Maybe he's just happy guy? Or he's happy to see you that day.
Show you are friendly and say hi