just happened with a colleague who got a new headset:
ATC: UAE88 climb FL330
...
ATC: ok and now you should say ...
ATC: f** why can't these f** f** ever listen %&@##* ???
...
ATC: crap, could be the headset
ATC: oh noooo...
...
UAE88: UAE88, roger climbing to FL330. Seems like your microphone got stuck, Sir.