What did you learn about people as a project manager?

In general I could say that people can make the difference. I know it's obvious, but the human factor is vital to reach results.

I tend to understand (and to monitor the situation accordingly) since day 0 who are the lazy people and the liars. 'They need to be properly managed

Farouq -

Lot of good observations given out here. Of course, Kiron's words of wisdom is too good.

I would like to add a couple of my observations.

1. People's response and output change positively / negatively while we work with them as PM. Some unexpected behavioral differences while you approach them as a colleague, friend and a PM.
2. I was able to notice few hidden talents and capabilities of people when we collaborate with them and they come out as true team players.
3. Project Crisis and escalations change some people's attitude adversely.