Why do I hate being told "told you so" so much? It upsets me.

It's like nobody believes so believe them. My little friend told me there was going to be balloons at the festival which I already know. I told her I know. When we got there she was like, "See? I told you there was going to be balloons!" Then my friends....okay yeah. I won't go into details. My ex boyfriend would say that to me a lot when he tells about things sometimes. He be like, "I TOLD YOU!" When his dog jumps up to get his treat like a cute trick. I wouldn't believe it and I was pretty stubborn. I hate when people tell me "I TOLD YOU SO!" I KNOW. I try to tell them but they either ignore or don't respond. Rude. My best friend even does that. I keep telling her over and over that I know but didn't respond. I kept saying it and she said, "I HEARD YOU!!!! I don't need to respond. God!" Just say something.