Some people are afraid of confrontation and for numerous reasons which include...
under-valuing themselves.
over-valuing others.
down-playing the infraction.
afraid of how the conversation will go.

Regardless of the reason, none of them are adequate. The only way to guarantee that others will consider us and treat us with civility is to request change when things don't go well. After all, we kind of lose our right to complain if we don't do something about it.

Conflict is going to happen. And people, far too often, don't know how to resolve it or are afraid to. Our presenting them with a request in quantitative terms and in a civil manner tells them how to do that, for now and in the future. It is very much a precedent. A signal to them that you won't let something go unnoticed even if it is small. And, sometimes, those are the more important ones because they tend to come first in an interaction or relationship. In effect, people test us.

Asking them to say they are sorry or saying something generic like "please fix this" is not helpful. It is a problem for you, so to speak, and you need to specify how it can be solved. If you can't do that, then either you don't have a valid complaint or you are not willing to put in the time to determine what it is, for whatever reason.

If you need, rehearse. Write down what you are going to say. Practice it with a friend. Tell them to role-play. Worse case the person can oppose you for saying what you did but, regardless, you have stuck up for yourself. We can work on the obstacles you may meet in another lesson. But, by all means, don't choose to avoid the interaction because you think it won't go well.

Be civil and calm as best you can. Be okay with messing it up. It is a skill that needs to be learned. But, in the end, it is one of the best, because it says "I value myself and am willing to ensure that others do too".