There’s some point to sitting where you are comfortable. I wouldn’t expect someone to sit somewhere they didn’t want to sit. However these people who get on buses and make a deal out of where they are going to sit after they get on a bus that I am a passenger on really stretch the amount of patience I have with someone having only a minimal impact on my existence.
I don’t see how someone can be that concerned about where they are going to sit AND be on a bus. Coming back from Salford this evening I was on a Finglands. Finglands are not the greatest buses: they are cheap and part of the price is reflected by lack of luxury. There are other buses running the route that are more luxurious (this is all relative) so people are making a choice to get on the scratty bus. And then inspect the available seats meticulously to check they are OK to sit on. Which all takes place while there are people behind them waiting to sit anywhere (but not at the front because they are leaving those seats for those lacking mobility).
Added to the mix is a woman who gets on and takes about three minutes to pay the fare of £1.50 in five and ten pence pieces. She is not fussy about which seat she sits on though. Some day there will be someone who pays for a fare in small coins on a budget bus company bus AND is fussy about which seat they sit on. You might think this kind of person is too much to expect from the human race. But we got to the moon and people thought that would never happen. Dream.