I purposefully give you problems yet I can also help you solve your problems, I give you instructions and guide yet I criticize you and point out your mistakes as well. I may know numbers, I may know how to sing or dance and anything in between. Who am I?

I whip and splash and flip all sorts of things. I mix and combine so much. And what I do is considered an art that after I make it everybody wants to take part. And when they do everything that I made is completely destroyed and ripped apart, which I am very pleased to see. Who am I?