Thrangu Rinpoche quotes:

meditation is not supposed to be the fabrication or the reinforcement of some particular state, but simply the cultivation of the awareness of whatever is arising in the mind.

There are several realms which ordinary persons do not perceive. Because they cannot see them, that doesn't mean they don't exist. One of these realms is the sambhogakaya that can only be visited by highly realized Bodhisattvas. In the pure realm of the sambhogakaya, the Dharma is continuously taught. One sambhogakaya realm is Tushita, which is presided over by the next Buddha, the Maitreya Buddha. Buddha Shakyamuni dwelled there before coming to earth to give Dharma teachings.

What's recommended is that if you have a good experience, don't get too excited. And if you have a bad experience, don't mistake it for a serious deviation or a sidetrack that you have to find your way back from. If you have a bad experience, just continue practicing as you were. In other words, whatever happens, just keep looking at your mind.