Whilst in principle I do exactly the same I tend to bit a bit sympathetic towards servers who at least explain when the problem is out of their control and due to shortcomings in the kitchen.
If they throw a couple of free drinks my way to ease the wait then that's a definite plus.
Those rather snboty servers who indicate a long wait for food is all part of the exceptional dining experience we're lucky to be enjoying get a big fat zilch.
The only time I'm prepared to wait any length of time for food is when my wife is too busy cleaning the house to get dinner ready.