Every dojo seems to have these people. Usually someone has to put them in their place. It annoys me as well. I am a new nobody where I am (been training 5 months) and at one point a senior student came back from a hiatus. This person was quite rough with me and appeared to be putting me in my place. Their hard throws didn't effect me any though since I am used to throws. In the end, a couple people told me that they thought that person was trying to put me in my place and show they were better then me. No problem... they ARE better then me! The part I didn't get was that I did nothing to challenge this person except for maybe showing up for class. For a while, every stretch I did, they did as well. It annoyed me, but I didn't let it get the best of me. Now we are sort of..... frenemeys if you will.
Oh, I didn't mention that this person is 3rd kyu and I am 6th. Again... what is there to be intimidated or feel threatened by. HAHA.
Some people just love to show how big their peni... I mean ego is. Just nod and smile, and if he is too rough, tell him you don't want to train with him anymore. You could also suddenly exploit an opening in his technique and throw him instead. That just might show him that he is not nearly as good as he thinks.