What is back handed compliment?

Back handed complement is a type of fake compliment or should we say when someone put your down or criticize you but by praising you. They show that they're praising you but in reality it's totally opposite.

Example.

These are some types of back handed compliments:

You aren't that good but today you are looking really good.

I never expect that you can do this.

Congratulations! You aren't so good but you passed with good grades.

I heard some back handed compliments from my friends and surrounding and to be honest, its really hurt.

Have you ever heard back handed compliment? From whom you heard it and how did you feel?