What is the difference between laughing with someone and at them?

It is more about the intent. If you are laughing at someone, it is more like you are laughing at their shortcomings or a failure or mistake they’ve made. If they’ve done something funny, and also find it funny, then you are laughing with them. Laughing at someone is usually not very considerate.
I like to tell people that I’m laughing for them, if they don’t see the humor that I see in the situation.

When you are laughing with someone, they may also be laughing – it’s a mutually funny situation. You both get it.

When you are laughing at someone, they aren’t laughing. They are being laughed at – which isn’t fun.

thanks guys

1st one makes the person enjoy it and the latter pisses him off.

It’s the difference between being an asshole and a dick.

Assholes laugh at their friends for something they’ve done.

Dicks laugh with their friends for something they’ve done to someone else.