Hollie Horror’s review published on Letterboxd:
Last night while I was watching Crystal Fairy I kept thinking, "wow, Michael Cera's character of Jamie reminds me a LOT of some people I once knew.." but, after sleeping on it, the familiarity in his jerk-like behavior is not a reflection of some of my old friends, it's a pretty accurate depiction of me in my early 20s.
I was incredibly impatient, especially if it meant hallucinating any time soon. I still have a low tolerance for people I find annoying though, that isn't something you really grow out of, I don't think.
If you go into Crystal Fairy & the Magical Cactus hoping for a typical stoner comedy, you will be disappointed (or for some, pleasantly surprised) as the movie is rather slow and paced, not negatively but in a moderated way (which is almost in defiance to some of the characters).
I would advise you that this isn't another "Michael Cera film where Michael Cera is Michael Cera" but that's not true, he is still his quirky, awkward self and I don't know if it's possible for him to ever be directed into a character which is not himself, but this isn't construed as negative for everyone, I find him rather amusing. Some actors are not character actors, because their own personality is character enough.