I doubt it bothers many people, but I've become irritated by the relentless "GB" and "Team GB" references in the media. "Team GB" was just invented to copy the Americans, but imagine how tedious it would be if it was "Team Argentina", "Team Italy", "Team Australia" etc. Using "team" is superfluous and unnecessary.
As for "GB", would anyone keep referring to New Zealand as "NZ"? I suspect not. Can you imagine classic Olympics commentators such as David Coleman and Brendan Foster referring to British athletes as representing "GB"? No.
We should just refer to our sporting representatives as "British" or as being from "Great Britain". Obviously there will be Northern Ireland exceptions, but "Team GB" and "GB" don't cater for that anyway. "UK" is fine as it's been in use for many years, but "GB" is new and just seems lazy to me!