Most: Open-mindedness
I should note the other highest are Kindness and Intelligence, but if you're either one (or both) of those but not open minded you become a very different kind of person that turns into a personality type I have a pet peeve for.

And those would end up being my least:
-Just Kind: The kind who acts nice, but silences out and is suddenly not kind to those who think or act differently (This is a huge pet peeve cause my Mom is like this)
-Just Smart: Knows a lot, but sits around just bragging about it making others feel dumb rather than listening to other ideas and theories that may also be Intelligent.
-Both: Less of an issue really, but still being stuck in their one way of thinking would wear off on me over time.