I wouldn't say it's this simple—there are lots of different strains out there with wildly different effects due to the cannabinoids they contain. Furthermore, every person's own endocannabinoid system is different, and reacts differently to cannabinoids. For one person, a strain might make them feel relaxed and happy—for another, the same strain might make them simply fall asleep (or extremely anxious, for instance).

There's also the very common issue of people new to cannabis using far, far too much—which generally results in a feeling of intense anxiety. Anyone who hasn't had any cannabis before should be extremely careful and use as little as possible.

Finally, regular users who have developed a tolerance for certain cannabinoids may find it difficult to relax without them. Anyone regularly using a substance like cannabis should be on the lookout for this, and change their behavior accordingly.