I have a long list, but top three might be.....
Swearing and bad manners - not sayjng please, thank you, excuse me etc.
Parents who use their kids buggies like a battering ram on the pavements and expect everyone else to move out of their way.
The use of 'text speak/spelling' in emails, letters, blog posts etc. It's invariably unintelligible and just sheer lazy.
Ooh I could go on and on........
Things you find stressful that other people don't notice.
Is there such a thing as delicious ready meals?
How do you acknowledge Easter.