Yep. I read it first on a fortune cookie! That was my original introduction to that idea that feelings come from ideas or thoughts. So simple, but so genius!
I couldn't stop thinking about it. I still haven't. I probaby never will.
We always say things or people "make us happy" or they "make us mad." Not true. You make yourself happy or mad by the thoughts you think.
If the thought isn't useful, or produces negative emotions for you, it's either not true, or you don't understand it.
Let your curiosity lead you. You'll learn so much about yourself and you'll find truth, joy, and answers to your questions!