A guy you knew commits suicide,what do you think about it?

I have had friends kill themselves. It's a really hard thing to deal with. I started looking back on all the things I did that might have upset him. Then I can't stop thinking about all the mean things I said when I was angry that I didn't mean. I wonder if I could have stopped him by just being a better friend. You know, a lot of people don't realize how much it affects people when someone does something that like.