1) Answering or speaking on a phone call via speakerphone – very inconsiderate.
2) A business answering a phone with “Hello” and not identifying the name of the business.
3) When passing someone on the sidewalk and the person would rather look down at the pavement instead of saying “Good Morning”, “Hello”, etc.
Interesting how so many of the annoying things listed have to do with the telephone or cellphone.