The best reason to be a jerk at work is that of course no one will listen to you or support you or embrace your ideas–you're a jerk.
The best reason to be a doormat at work is that in your effort to get along, to be nice, and to go with the flow, of course you won't be expected to stand up and shout, "follow me" when your ideas might take you in a different direction.
Both extremes are the refuge of the lizard brain, the voice of the resistance. They reward the desire to fit in, not to stand out.
"It's not my job" is a comforting refrain when you'd like to hide out. So is, "they all hate me and won't do what I say."
Fear is the driver here, it's fear that pushes people in either of these two directions. That's because in between the two extremes lies responsibility and opportunity and the requirement that you actually do work that matters.
The hard part, the part that gets you rewarded, is understanding that sometimes it is best to use common sense and toe the line, while other times you are facing fear that must be overcome.
Linchpins might be afraid, but they know precisely what they're afraid of. And then they do something constructive about it.