The sonic screwdriver is a device in the Doctor Who series that can open any door, scan for alien life or radio signals, deafen any enemy, lock any door, and rarely to drive screws.
As you can clearly see from this description, in the hand of the Doctor - the protagonist - it is quite a useful device in any situation. Unfortunately it is used constantly and too conveniently in almost all the episodes which makes it a very easy way out for the writers of the show. It makes them lazy as they don't have to invent any MacGyverisms as they can just rely on the good old screwdriver to get the Doctor out of any trouble the writers have put him in. I think it would boost the creativity of the whole show and thus its quality if it was written out of the show for a little while, as it was in 1982 when the then producer, John Nathan-Turner had the same opinion about it as I do now.