I like to trip alone. Sometimes there is nothing better than some personal "decompression time" with a few hits of LSD, my iPod and some quality phones of the head.
In fact, some of my interesting experiences in life--ones that have taught me most about myself--have been little more than a free night, some good music and a psychedelic (5-MeO-DMT being one of the most introspective that I've tried). Also, I will usually always evaluate a new psychedelic compound by myself, so that I am free of distractions and can really assess the effects in detail.