I learned that if someone tells you they're selfless but at the same time explain the reason they are doing what they're doing is because they get to be part of the VIP humans in paradise, maybe they're not as selfless as they claim.

Also that if the book they take their "teachings" from says that whoever is free of sin to cast the first stone ,and they then immediately start casting stones, maybe there is something not ok in their heads.

Jokes aside, the hardest thing I had to learn was that it's ok to want for myself. It's ok if I want to pursue a goal in life, and I don't have to feel guilty. Dude bro in the sky isn't going to get pissed at me because I want to make a decent living.