It's always good to offer your seat to someone who obviously needs it more than you but sometimes it's not obvious and hard to distinguish. I always try and offer my seat to a pregnant lady or the elderly or disabled - I very rarely do not.....but I myself have a heart condition and I have a heart monitor inside my chest - standing for a long time sometimes makes me dizzy or if I've had a bad 'heart' day then I need to just sit and get home as quickly as possible. To look at me you would never know, but I'm sure on some of my vary rare occasions when I haven't stood up I was being judged. Sometimes people do need the seats but their conditions are not as obvious as others.....and some people are just ignorant and stay seated because 'they've paid for a ticket'..... .....o and about standing up so people can get off - my balance is poop too, so I stand up when the bus has stopped, genuine safety reasons.