This.
I've tripped plenty of times on LSD and methylphenidate, and didn't have any issues. Except maybe overstimulation since psychedelics can be somewhat stimulating to begin with.
I would not encourage anyone to quit their SSRI to trip. Yeah, increased serotonin levels caused by antidepressant treatment seem to result in a higher baseline tolerance toward psychedelics, but so what? Unless your antidepressant also specifically blocks 5HT2a receptors (like trazodone, mirtazapine or the tricyclics do), you can trip just fine, it's just going to be slightly less intense... which you can compensate for anyway by taking a slightly higher dose of psychedelics.
The psychedelic experience is heavily affected by set and setting. Discontinuing an SSRI tends to cause temporary irritability (not to mention a potential relapse into depression in the long run), and a cranky/depressed mindset is much more likely to lead to a shitty experience than a slightly underwhelming dosage. Plus, some people tend to react more strongly to psychedelics than others, so if this is your first rodeo with shrooms, you might want to lowball the dose anyway.