Not working harder in school.
I did the bare minimum to be considered a “good” student, went to a fine state university, and do well now but my siblings went to elite universities. My older sister went to Yale then Columbia’s medical school. Now she’s a cardiologist. My younger brother went to MIT and works for Google. I went to University at Buffalo. The school was fine but it’s obviously not Yale or MIT.
Letting my mental health control me.
Not punching the guy who run over a skunk on purpose
The last conversation I had with my Dad was a huge fight on the phone. It was my fault and I was being dumb. He didn’t wake up the next morning. I should have listened to him more. There is nothing I wish I could fix more.