The reason this is the case because everyone has the natural inclination to want to participate in the roleplay. Now, characters would be inclined to be afraid of other characters if said other characters were proper mysterious and unique. However, since everyone's more or less encountered every body else, the mystery is gone, and the only Fear you'll see is residual from, like, an asskicking suffered in the past.
A lot of the characters on the board are like the X-Men at this point. They've been around the block a few times, and they're not about to poodoo their trousers over a cosmic, world-ending threat. The most pervasive character occupation is something to the tune of "Adventurer," so you're going to see more adrenaline junkies and folks who react to threat with Fight over Flight.
But, really, if you want people to think you're scary, actually be scary. Don't expect them to cower simply because it's possible that you may be able to kill them. EVERYBODY EVERYWHERE may kill them at ANY GIVING TIME. It's a world where PTSD doesn't exist because it's the normative sentient experience.