Don't get me started!
Cyclists two abreast.
We are dog walkers and try to be considerate to others. If we see people cycling/infirm/wheelchair/buggies/toddlers and so on, we call our dogs, hold their collars or put them on leads so said people can get past us. I have lost count of the people who have stopped for a chat not even acknowledging we are standing there like a pair of twits holding collars for them to go by, not thought to say thankyou, whizzed past nearly knocking us over, or, once, incredibly, had a go at us for even being there.
I always thank people who let me pass, open doors for me, or other acts of politeness/kindness.
And it's not just the young. I once made the mistake of visiting my local supermarket on 'pensioners money off day'. I was crashed into by trolleys with arguing pensioners. Some of them with trolleys full of alcohol. Rudely pushed out of the way so they could get to things. Shelves blocked, such rudeness I was shocked. Then to top it off, I witnessed an actual punch up in the carpark between two elderly people over a parking space.
So it's not always the young people. Some are lovely and polite.