I think some of how much stuff bothers us is our own point in our lives. The more life in general is bothering us the more others bother us. When we're at peace with our lives, we often don't notice this stuff at all. On the other hand, we all have habits and behaviors that are truly annoying and everyone would be happier if we just stopped doing them. What my wife and I do is dig at one another until we hit a sore spot and then we get mad and then we yell and then we hate each other and then time passes and in our relationship I'm the one who is the peacemaker, my wife would be just as happy with nobody else in her life at all. So I guess part of it is, the more adaptable person has to just accept the annoying parts of the other person. I think most humans are pretty full of disgusting and annoying behaviors, and we get along by mostly just ignoring them. The more we focus on them the more they bother us. Acceptance goes a long way, and if the behavior is truly unacceptable, it has to be confronted, which leads to a fight, which leads to time passing, until it happens again. Which is no help at all but that's life.
Irritability can be a symptom of many different things. I know that I am starting to get off track when little things start really annoying me that usually don't bother me. I have found that the best way that i can deal with this is making sure that I am doing good what I like to call maintenance self care. Find things that you can do routinely to manage your stress. For me it is limiting alcohol, going for nature walks, stretching daily to relax muscles, reading, getting to bed at a reasonable hour,etc. I notice that when I do this I am not letting my stress build to the point that I get annoyed.