The habit that annoys you most in other people is worth checking for in yourself.

Strong irritation is often recognition. You spot the behaviour instantly because some part of you knows it well, and the sharpness of the reaction comes from how uncomfortably familiar it is rather than from how bad it objectively is. Not always, but often enough to be worth a look.

Take the thing that gets under your skin fastest and ask when you last did a version of it. Ask somebody who sees you often, because they will answer quicker than you will. If the answer is yes, that is useful rather than shameful, and easier to change in yourself than in them.