Threads about the irritating things people say tend to get very lengthy on AB!
One of my current pet hates is the increasing number of people, who when ordering something in (say) a pub or fast food restaurant, use "Can I get?" as a substitute for "please". So, instead of "A pint of lager, please", we now hear "Can I get a pint of lager?". (Horrid Americanism!)
"Upcoming" also annoys me. It's another Americanism that seems to have crept into British Engklish, replacing "forthcoming" (which I much prefer to hear).