Tuning

Why do people play all kinds of stuff during the tuning note? I guess this is an oboe player's obsession, no one else probably even notices. I stress more during those long As than any other time, at least for this concert. I worry about if it will be in tune (always use a tuner) and if it has good tone - when I've gone to hear the great ones (eg Cleveland, Chicago types) the A is glorious every time! I just want to hear that person play one note, it is so good. Of course, no one is yakking or playing some cello concerto during the tuning...to be fair, no one in our little orchestra does that on concert night (thank God). Just a little thought for concert day.