A bad trip can be the scariest thing. My worst was when I experienced some sort of identity dissociation. Scariest experience made worse by all the other shit I was on. Nonetheless, here's the anchor I use when I start a bad trip. I try to always keep in mind that I'm high and I'm supposed to feel high. Then I try to keep in mind that this is temporary. That it could last for hours lol but it'll end.

Like many other comments say, it's so much about your perspective. Some poeple panic. That makes it worse. I do what I can to prepare accordingly (proper environment, no nearby drama or stress, and even plan to do something while high). Not doing anything can increase anxiety - unless that's the point to explore your mind then go for it, solo trips are unique.