What if I don't go to jimmy johns because I forgot to tip?
Are you doing that as a form of self repentance?
Yes I have a weird self punishment tactic going on in my head
It is good to tip those who serve you. However, if you simply forgot, you should not punish yourself about it.
Sorry I just don't tip and also my parents taught me that it's rude to tip.
Society expects people to tip when they are provided a service. It's considered rude to not tip, which is why you felt the need to punish yourself for this. Just try to tip in the future so that you don't have a need to be upset with yourself.