My 4th time doing acid was the first REALLY strong, intense experience (had good times before that but not amazing), the trip that made me really fall in love with LSD (I'd had very intense shroom trips before this though), there's definitely something about my first really intense shroom & LSD trips that was really special, the newness of it all I guess...I guess it's because after that you're somewhat used to it, it's not as shocking.
But I've been taking psychedelics for like 3 years since those experiences & I'm still just as in love with the experience as ever, it's actually much more useful now (and has been for a while) than it was back then, I know how to harness psychedelic experiences now, I appreciate them in a different way, more thoughtful & aware, more balanced & less obsessive.
As well I had many experiences more out of this world & insane than any of the earlier ones, even the strongest of those. The astonishment of the early experiences, the freshness of the more recreational effects, euphoria, body high, visuals, just had a particular intensity & sense of awe, back then I never could have imagined experiencing such amazing things, now I've experienced them over 100 times.
I always take high doses & have for a long time, as well, lower doses really only were mind-blowing when I was newer to tripping...this doesn't mean I go all out every time I trip, but I always take fairly strong doses. Many people have lower sensitivities to psychedelic drugs, though, I am a hardhead, & as well I tend to get pretty heavily into anything I like, going deep with psychedelics just comes naturally to me, works well for me.