Okay thought this may raise a few smiles! I'll start - Websites that show items in stock then once you have completed the payment details you get an email telling you they are out of stock and will forward the items as soon as they come back into stock!!!! Anything else???????
Going into a coffee shop and finding it stuffed to the gunwales with yummy mummys, their noisy offspring plus push chairs ( large ), shopping bags, tote bags and sufficient extra baggage so as to ensure two yakking occupants can take up the space allowed for four or five.
People who dont consider others on the road , barge thru when its your right of way , no manners . stop Botox
People not looking where they're going cos they're too busy texting (I swear, I'm going to yell in someone's face one day...) People stopping when they get to the top/bottom of an escalator and nearly causing a pile up cos they can't decide which way to go.
Lots of things, mostly what has been posted above. Although at this time of the year the most annoying thing is pig ignorant tourists, their repulsive off-spring & general behaviour of both the adults & kids. Joys of living in a holiday area :-