[Sundae]

People who make a big deal out of getting off the bus or train quickly, then meander along at a snail's pace. You knew you were in no hurry, or move fairly slowly, so why not chill out and let faster people who are in a RUSH get off first.

I was taught this as good public transport manners.
It might be a generational thing, because it's generally people older than my parents who do it.

And people who are surprised that they have to pay for their shopping.
"That's £31.15 please." THEN they start rummaging in their bag for their purse!
This - sad to say - is almost exclusively a female trait.

The only time it can be forgiven is if people are holding shopping in their hands and so have no spare hand to retrieve a method of payment before everything has been scanned through. Still irritating if it's the person in front of you though.

Oh, and this one is really quite unfair, but I hop from foot to foot with rage if I'm stuck in a Post Office queue and EVERYONE ahead of me is having their passport processed/ paying car tax or has a really complicated query regarding what they are sending abroad. I forgive myself a little of my unreasonableness because it's mostly directed at those who hold up the queue and walk away without completing the tranaction because they haven't brough the right paperwork or haven't filled it in completely.

But I do wish there was a fast-track queue for people who just want to send a postcard to America. Or withdraw under £10 from the counter service or any transaction that lasts 180 seconds or less.
Oh, I seem to mean a fast-track service for ME!