Why does causing someone else misery seem funny?

Schadenfreude.

I'm not trying to repeat what everyone says but if you really like witnessing other people's misery, you have either psycological or depression issues yourself. Have you ever heard the saying misery loves company? Well, you're misery and your victims are your company. You seriously have NOTHING else in life to be thankful for or smile about? I'm not trying to criticize you in the least bit, but please find another hobby. My only concern is you never know what kind of day yor victim was having. What if that particular person is antagonistic and has no remorse for the actions they take against you whether at that particular moment or in the near future? How will you react then?

People usually do things like that cause secretly they may be jealous or just plain cruel and they hate to see others happy while they're miserable inside. My sister once planned to have one of her guy friends pretend to lead sone girl she didn't like on. On top of that, they tried to go as far as to make the girl fall inlove with my sisters guy friend then have him humiliate and dump her in public! Her intensions? Just to make the girl feel worse than she already did about herself, and bring her own shallow self esteem up a few notches. That's usually the case :(

There is something wrong in you... If you feel happy towards someone else misery.It is a sign of insecurity. envy, hate and the like. ^_^

Yes. This is called immaturity.

its funny because its not happening to you lol