As long as they can be difficult without being an asshole, I'm ok.
I disagree. I avoid toxic people and those who waste my time.
There is a difference between “difficult” and “takes work”. All relationships take work to make them last, but, you shouldn’t have to work so hard the entire time, day in and day out. It should be a give and take setup. At least that is what I imagine successful relationships are. If they are so much work that You are miserable it’s time for a change.