Perspective is everything, that's for sure.
I think personality and sleep needs play into it too. I tend to be a fairly low energy person anyway, so sleep deprivation of any kind is especially rough on me. I can see how it might be different for different people as well.
(Although after having a baby who woke up every 20 minutes for over 2 years, I have a hard time sympathizing with people who are tired because their baby nursed twice in the night.
)