Michaela's sister

Sorta funny story.
So, I spent more time with two of my friends from high school. One of them, like I mentioned, I knew. I saw him at Jade's graduation from nursing school and at my reunion. He knows my brother-in-law and so our paths have crossed. Or, I suppose we are familiar we each other.
The other guy, I didn't know in high school. He is two years older than me and we frequented different social circles. I did see him at my reunion and I did know who he was. I asked him the other night, if he knew who I was in high school and he goes--sure, you were Michaela's sister. Nice.
I suppose many people knew me like that in Salina. Michaela was the homecoming queen and I just wanted to run as fast as I could from Salina. It still makes me laugh. He did mention, of course, that he had a crush on her when we were in school. My question to him was--who didn't?
And now, when she comes to visit me, she is Harmony's sister which is great...I suppose.
The last few days have been interesting in terms of etiquette. I had three completely different, yet equally frustrating situations. I think my favorite happened at Elway's. I was dining with Jeremy and Aron and Elway's was packed. When we approached the bar, I found one bar seat and told Jeremy to sit down since he had torn his ACL and needed to sit down. There was a solo guy on the corner and it was obvious that he would be a quick diner. This older gentleman approached me and told me that I should sit down. He insisted. I told him that it was nice and I appreciated especially since my friend tore his ACL and I wanted him to be able to sit down.
A little bit later, this other guy comes up to me and tells me that I am rude for sitting down in his friend's chair. I couldn't believe it and I tried to explain to him that his friend had insisted that I sit down. He told me that Jeremy should offer me his seat. I told him to sit down and continued to defend myself and basically tell the guy that he wasn't involved.
I couldn't believe the audacity of this guy. I mean, it wasn't even his chair and why did he care?
Eventually, he apologized and I told him no worries. Seriously, what is going on with people?