When things don’t go the way I planned, how do I avoid getting angry about it?
So, instead of being disappointed, you should say, “I thank you, Hashem, for that lesson. It’s worth money, that lesson. I really should have to pay for that lesson. Thank you, Hashem.” Because otherwise, you think that you’re the boss. You think that you’re the whole boss. You’re the whole מאכער here. So, הקדוש ברוך הוא says, “No, no. You’re not the מאכער at all. I’m the מעכער.” And that’s why things turn out the other way. Not the way you planned. Hashem is telling you, “I’m the מאכער here!”
So you’re getting a free lesson. And הקדוש ברוך הוא is not charging you for it, so be happy.