I used to care about deadlines, then I realized that very few of them are real and the consequences for missing them were minor. More times than I can count I pushed myself and my team hard to meet a deadline only to find out that no one else on the larger program met it or that it was artificial. Now as soon as someone gives me an urgent deadline I ask them for the real one and force them to defend it - doesn't matter if it is another engineer or the lab director.
The only ones I really care about these days are the ones for submitting proposals. Those appear to actually matter.