Simply ask the question, "if I change this part of me, will I still be me?"
I cannot speak for anyone else, but there are some parts of me that are integral in my personality or identity. These parts, if I remove them, makes me feel like an alien to myself. Therefore, I will try not to change those parts as much as I can.
On the contrary, others I change readily. Bodily appearance is not part of my identity; hence I would change them if need be, even to the extent of using plastic surgery.
If you get an ambiguous answer, you can experiment with changing that "trait" of yours. Notice your experience while changing it. Notice the results. At the end of the experiment, ask the question "am I still me?" If you can answer yes and the result was positive, then by all means change. Otherwise something needs to be tweaked.
Be careful about defining a situational response as a disposition. You may only be arrogant to certain people or under certain circumstances; this is not a disposition. You only need to find the reason behind your situational response and find a solution to that.
People who know me would describe me as being benign most of the time, but I can be overly critical when certain ideas are violated. If I find that people are not doing enough justice to these ideas, my critical voice will emerge. The fix could be to adopt the belief that "people are just different, so they will always have different opinions from mine."