I haven't counted the number of times or exact dosages I've used it at, but I'd call myself experienced with it, usually dose 15-25mg, dosed 30+ a couple times. I have never had changes in thought pattern lasting into the next day even. As soon as I get some sleep I'm back to normal, visual static will increase after using, especially if I do so multiple times in a week. My worst experience with the drug had me bored, and I can pretty much count on it to be an enjoyable experience (may be neutral if I'm using too frequently). I want to say I've been using it regularly, ~once a month, (sometimes more, sometimes less) for a year-ish, but I had experienced it prior to that. It was also my first psych, btw.
And our point isn't that you and the others weren't negatively affected by this chemical, or that there is a portion of people prone to such negative effects, it's that lasting negative effects can be caused by pretty much any psychedelic. It just depends on the person and circumstance. It'd be nice if we had a scientifically viable statistic to show what psychs or groups of psychs caused serious issues for whatever % of people, but we do not.