One of the ideas I have heard often and find so difficult to internalize is the flaws which bother us in others are our own flaws. What does this really mean?
I think it is best by example. I have noticed a characteristic about my siblings that really bothers me. When they get something in their mind that they want, they harp on it and harp on it. I was telling my family about my kid sister. When she was 13, she wanted to have a 32 picture wallet like all her friends and her birthday was coming up. She talked about it so much, she got five for her birthday. My family said, "Dad, you are just like that." I can tell you I am not aware of that characteristic but if I have it, I would agree it is a flaw which I would like to change. You can hear in my story that I cannot see it in myself but I sure can see it in others.
The point is if it was not a personal issue for me, the flaw would not bother me in others. I would observe it but it would not bug me.
So what do I do about this issue? I think one thing I might do is ask my family to point out to me with some playful code word that I am up to my mischief. An example of the code word might be "Do you want a 32 picture wallet?" If I can laugh at myself, I will drop that flaw quickly.
Another example I recall is using non-words in public speaking. I would use "Ah" or "In fact" repeatedly in presentations. The same characteristic would drive me bonkers in other people. In some training I was taking, the trainer asked the class to click their fingers every time I used one of my non-words. I heard the first click and never used those words again. I was amazed how quickly they disappeared.
So if you see something that really bugs you about someone else, ask a confidant if you have the same flaw and then if they say you have it. Elicit their help in removing the habit in fun way.