Bus number 31 from Oslo centre is most of the time quite full if I take a bus from the Railway station and maybe up to four stops after that. I have noticed that I often get a seat fairly quickly if I get in at the back. Often there is a free seat or someone offers me theirs or someone gets off. I'm close to eighty but do not have problems standing, yet it is nice if I can sit. Some days ago it did not work so well.
I got in at the back but all the seats as far as I could see were taken. Then one came free but before I could react, a guy about 30 took it. Soon a young girl also took a seat which came free just in front of me where I was hanging on to the post. Not enough with that, the first guy left and before I had time to move, the friend of the girl slipped into the seat! This always never happens, people always even tell me: "here's a free seat." if I have not noticed it. There might have been seats in the front of the bus and usually people leave half way to my destination but not this time. None at my half of the bus moved until there were just a few stops left.
It reminds me of a funny incident. I was in a bus that was almost full. There were a couple of free seats in the front behind the driver where she could not see them. She said to the people: "Cannot you see that a lady is standing, please give her a seat." As there were free seats, no-one moved, so she repeated it, a bit more forcefully. The confused lady looked a round and said: "Do you mean me??"