Sometimes anger results from expectations that are either too high or that aren’t consistent with the expectations of those around you.
You enter a situation and expect things to go smoothly, but then something goes wrong- maybe even predictably wrong- and you get angry. If you had entered that same situation with the expectation that you may encounter problems, you likely would have reacted to the barrier differently.
Alternatively, you likely get angry sometimes because you don’t communicate your expectations to those around you. You think you’re on the same page regarding plans or shared interests, but then discover that they were thinking and planning on something very different. You get angry and disappointed as a result.
If you adjust and communicate your expectations in advance to include the possibility that life can be complicated and doesn’t always go as you hope it will, you’ll likely feel less anger when things go wrong.