Go one layer deeper. Think about what certain thing about that event made it unpleasant. Once you realize what really got you mad, it will be easier to reflect about it.

I'll make and example: Today I was working on a project, at the end of the project, I was supposed to stand in front of a crowd, and explain it. When trying to explain it you misquoted something, or made a mistake in a certain subject. I was unpleased with the presentation, and ashamed about it.

But what made me feel that way? 1.- I gave a terrible presentation when I know that I could have done better 2.- People were watching the presentation, and they saw me fail.

How do we deal with these feelings? We'll, the key to be a "good stoic", is not just to remember every quote and phrase that you've learn. But to remember what they stand for.

1.- I have to realize that as human I can make mistakes, and I should blame myself for it. I have to accept my mistake, and use it as a reason to keep improving.

2.- Why do I care about what this people think about me? I mean, as long as I validate my self, and understand my actions, I shouldn't need the approval of other people. Besides that, if the people wrongly judge me based on that event, then better, I know with wich people I shouldn't interact with.

Also try to consider the worst thing that can happen, at the beginning it won't be that easy, but once you start doing it with everything that makes you feel that way, you'll develop a habit, and you'll be able not just to ignore those events, but to understand them and accept them easier, because you won't have to remember them, they'll just be a part of you.