The glovebox hinge on A4's have a damper to allow the lid to drop gently. Over time these get stiff and they WILL break the hinge. For ages I've been thinking "Soon I must lubricate that damper" - but I left it too late and the hinge broke
This will take you one minute at most!
Pop the end of the dashboard on the passenger side and you will see the damper. Lubricate the barrel with a silicon type lubricant and replace. Save yourself the griefy glove box fix!
Credit to Marc1 for the following: It is possible to remove the damper and split it and take out the O ring which provides the damping. The glovebox will still work fine but the damper will not be stressing the weak hinge.