I had it when I was a late teen, enjoyed it, took it again a number of times (7/8?) into my early 20s, but by the last time I just found it boring. I think most people have some fun with it and move on.
Asking for a friend.
I knew at least one person who was a tripped out mess every time I saw them.
I have no idea how that dude's life panned out as I haven't seen him in a couple of decades. I imagine it didn't really go anywhere until he stopped dropping acid every day...
Some people report HPPD from repeated use.
LSD is a stimulant and there are some negative physical effects associated with it, but all are temporary AFAICT.