I have two seperate friends who have multiple stories about Cuban and what an awesome guy he is.
Think I already told these stories here but...
One friend is a makeup artist and she says he's by far the nicest celebrity she's worked with and besides being super nice he hooked her up with all sorts of merch, she raves about him.
Another friend is president of the dads club at his kids' elementary school. A group of dads who meet at school periodically for breakfast with the students. And do other stuff to support the school. Now and then they get a guest speaker to come and speak at breakfast. He randomly cold emailed Mark Cuban asking him if he'd come speak to the kids, thinking there's no chance in hell he would hear anything back. Cuban replied like a minute later and said sure, happy to, when and where do you want me. Was as easy as that. Completely cold email to a guy who probably gets thousands a day. Cuban showed up at school alone, drove himself there, and gave an amazing talk then hung out with the kids for a while.