I was at a baseball game recently and it was getting into the 2nd or 3rd inning and I put my foot up on the seat in front of me. No one was sitting there so I didn't think twice about doing it. The guy one whole seat over asked me to take my foot off of the seat. I admit I was a little annoyed but I obliged. I said, "Sorry about that that" and moved my foot over yet another entire seat. So now there are two entire seats between his body and my seat. I asked him, "Does this bother you"? He then moved the two seats over and and with both hands flung my foot off of the seat. I will admit that I was angry and in my anger I asked, "what the fuck is your problem"? Or something similar. I was angry enough that I don't remember. (I've texted my BIL to see if he remembers if any of you care or think it is relevant.) Suffice it to say it wasn't nice whatever is was. He refused to look at me. Now that there was someone sitting in front of me I refrained from putting my feet on the seats. 

However, after that I went from peacefully enjoying opening day with my BIL to being angry. I saw that he was wearing a jersey from the other team so whenever my team did something good I cheered obnoxiously. We were down by a couple runs at that point so there wasn't much to cheer about. For example, loud clapping (more than was necessary) and high fivng the people around us like it was my job. After a half inning he left and did not return. I'm assuming to find better seats. 

I don't want to mislead you fine people but, before the incident I was sitting in the sits doing what people do at baseball games. This guy didn't even exist to me. There was no previous conflict. In fact it was pretty serene. I was just thinking about maybe getting a hot dog when this all went down.