"I don't like it!"

I was doing something silly(shooting water with a toy water gun) to Peter, and instead of giggling like usual, he said:"I don't like it, mama!" Well, I was a little surprised but stopped anyway, since you know, finally my boy began to use his words to describe his feelings, and I should respect it, right?

Peter then grabbed the water gun I put down and began to shoot at me. It did not really bother me too much, but just for fun, I told him "I don't like it, Peter!" in a firm voice. Peter's reaction was: he paused right away, looked a little shocked--guess mommy has never stopped him from playing before for no reason. And then, realizing I was still smiling, he aimed the water at me again. Before the water came out, I did it again"Peter, mama doesn't like it."-----Guess what, Peter came up to me, big head on my shoulder and began to cry so badly.

Obviously it is easy to tell others while harder to accept being told "I don't like it".