You could call them "smiley" or "cheerful."
Usually you can tell when you look in his eyes. When we are really happy - we smile , or cry but always with the eyes involved. If you see someone smiles, but his eyes are not 'part of it' - you can tell he fakes it.
A person who believes they are sick or even creates illnesses, is often called a hypochondriac.
Yes it is dificult not to smile when someone smiles at you.
No baby
wonderful.....noone can't like someone that smiles............who doesn't want to be smiled at?
Munchausen's Syndrome
When you make someone smile .
Such a person is often described as serious, stoic, or reserved.
Poker-faced.
I believe it is just a joke. Meaning that if something goes wrong and a man smiles about it, he has found someone to blame.
either your in love, or you are remembering a funny memory with someone special