smile, smirk, laught at, sneer, and chortle

There are many different ways to laugh
When you smile, you are happy.

smirk: v. o smile in an unpleasant way because you are pleased with yourself, glad about someone else's trouble, etc.

When you chortle, you still are pleased with yourself but not in an unpleasant way.

When you laugh(or sneer) at someone, you show no respect and may hurt the person.