Cell Phones - are they a nuisance in office

I dont know whether I should be writing this or not as I also own a cell. In most of the offices , one might be hearing a mobile phone ringing at some time or other. It not only detracts others , but it also reduces the productivity of employee.Why cant people keep it on vibrator mode, and to add fuel to the fire, people keep on chatting on the phone for hours without taking into consideration how inconvenient it is to fellow workers or how their prodcutivity is going down.Later the same people will crib that they dont find the work challenging, How can you when half of your working time you are talking on your cell.

I am not against having cell phones , but people should also impose a self discpline