F.Bullbait
Oh, a wise guy,eh?
I would say that there is the danger that a person will have "a bad trip", and it CAN be deeply psychologically damaging if you become extremely anxious, or paranoid, and never transcend it.
As Timothy Leary put it, it's about set and setting. Your psychological set contributes greatly to whether you'll have a good time or not. It should always be taken seriously, and understood that it is a risk. After the first few times, once a person knows what's happening and how it goes and what to do, or not do, they should be fine. That first time is where the danger lies. I won't deny the danger is there. I'm just glad I was a person who was not negatively impacted. I had some bad times, but nothing that hung with me and hurt me. It's very much a "rite of passage", and some people do not make it through safely.
Consider yourself lucky if you've never taken a hit of bad acid. First time, 100th time, doesn't matter; a bad batch will screw you over royally.