What do you mean "treat people a I say I would"? I haven't mistreated anyone. I have, however, voiced my disapproval when people have pissed around and left a project to the last minute. That isn't me being ruthless, that is me saying "thanks for putting me/my team under stress because of poor organisation".
And whether or not you leave things to the last minute is not proof that "Parkinson's first law" is true in every case. It is true in cases where people take the piss. It is true in cases where projects are mismanaged. Like I said, if I get a request to do something immediately because the deadline is in 5 minutes, and it isn't my fault then I'll make it known it isn't my fault. Oddly enough, I haven't been sacked once. I've walked out of places, true, but I've usually done that knowing I am walking into something better.