Now, I'm no fan of mobile 'phones but I don't, generally, have an objection to other people having one.
Except when they forget the bit about them being mobile.
One of the horrors of the modern office, which God knows is Hell on Earth to begin with, is the mobile 'phone that somebody has left on their desk while they go away and play with a photocopier, get a butty from the shop down the road, go and gawp at the bloke who's brought in the new literacy group, that sort of thing.
So there we are, stressed out, running round taking telephone calls for people sitting in their offices not taking telephone calls, in between trying to keep at least one wheel left on the wagon. And then you hear something shout: "Answer me you bastard!" And continue to shout "Answer me you bastard!" for the next five minutes until the caller cottons on that nobody's there. Then, just as you settle down after this nonsense, somebody else's 'phone starts playing some bit of (c)rap music. Very loud. And repeat... Then "Answer me you bastard" tries again. And then a cock crows...
Do your workmates a favour before they kill you: either carry your mobile with you so that you can answer it when somebody rings you or else turn down the sound. A lot.