Re those people on buses who plonk bags on the seat next to them, and then pretend that they haven’t noticed other people having to stand - I will just say nicely enough, ‘Could you move your bag, please?’ I do get the odd eye roll but that bothers me not at all, and nobody’s ever refused.
What amazes me is that so few people ever ask! Why not?
On the same tack, not long ago on a very full bus, a young man glued to his phone was standing in one of the buggy spaces, I think genuinely oblivious to a man with a buggy who had no option but to block the aisle with it. But he didn’t ask the bloke to move - why on earth not? I eventually did - nicely! - and he moved straight away to make space for the dad with the buggy.