I think it is important to keep positive in the moment and realize that you shouldn't beat yourself up for your mistakes. I made the huge mistake of leaving Dave's keys in an Uber... but in the end, it was really an interesting experience, and I think Dave and I definitely grew closer as friends haha!  The important thing is that you keep your head up, and deal with the situation you are faced with, without dwelling too much on the past. It's important to learn from the past, but not to be hard on yourself about past actions to the point of not being able to function in the current moment.