Interesting question, I know. For me personally the answer is no - I have not ever regretted having gotten into bitcoin, despite having spent hundreds and hundreds of hours researching the topic. It's always been an interesting ride.
But I have a friend who got scammed and he regrets having had anything to do with crypto in the first place. It's pretty sad but there's nothing I can do about it. I even offered giving him half of the amount he lost from my own crypto stash (mind you I am not rich) but he's so scared that he's not interested any longer...
Only thing I regret is not getting involved with it earlier. As for your friend, there isn't much you can do right now except to explain to him that it's still relatively early in things and until some things are sorted it's unfortunately still possible to get scammed. Have him try again later on once things are more along the way and things are easier for newbies. Perhaps every now and then show him cool stuff that's being done with blockchain & crypto as a whole.