Is Karma Truly A Bitch?

I believe in karma. I believe if we do something bad to someone consciously then we will receive the same treatment in future. But..

What exactly is bad karma? How if, an action of mine was done because I feel like they deserve it? Will karma attack me? 

Also, how if I did something to make me happy and it is something classified as wrongdoing or something which is not socially acceptable by others? 

Is that means I will have to go through a punishment soon in the future while I simply did that because I wanted to be happy?

How if I did indulge in something which is completely wrong in my past, will my future do the same to me in the name of karma?

When exactly karma will take place? How if I believed in my wrongdoing? How if I don't find myself to feel guilty? How if my actions were right at that moment of time and my future says it is wrong? 

Was I really doing something wrong in my past then? Will my future punish me with the name of karma? Does karma ends in the past or it will keep haunting?

Is karma truly a bitch?