I wasn't super sure how to word the question but here are some of mine that I've enjoyed coming across:

"Dads are parents, not babysitters!" (And seriously, this should go without saying.)

"Being "family" doesn't entitle you to physical affection from someone else's kids." (I will never understand the family entitled mindset. Just cuz you're my grandma doesn't mean I have to sit in your lap. Just cuz you're my potential MIL doesn't mean you get to run my wedding. Sheesh.)

"Your trauma is not your fault, but it is your responsibility." (I love this one because I've noticed this a lot with all the teenagers I come across who blame all their troubles on the world and refuse to change because they think they shouldn't have to. No one's invalidating your pain bro, we get it...but we're not all going to walk on eggshells so you get to stay an azzhole either.)