OK...this happened on a Delta flight but could happen anywhere. I just want to see what people here think of this.

I was boarding a plane (light passenger load) and there was a gentleman in my seat. When I told him it was my seat he, very snotty like, told me there were plenty of open seats elsewhere. So I told him correct you should go find one. He was visibly upset when he realized I was not kidding and he needed to get out of my seat.

Should I have not said anything and just found another seat? If he would have been polite upfront about it I would not have had a problem...