I'll put my two bob's worth in ...
Sometimes you have lots of time to plan, and if so, do it diligently. Other times, you don't, and have to do the best with what's available. If you're really too rushed, make the safety call and don't fly.
But are you really too rushed? What about when you're airborne and have to cope with an unexpected diversion? Apply some of that quick thinking to your preflight planning - the more you practice, the easier it gets.
Lastly, keep in mind the more time you have, the more you tend to waste, so while you may feel rushed at times, consider how quickly you can really do the job while still covering all bases - sometimes we work better under (reasonable) pressure.