Bad trips have been the most valuable trips for me, the ones from which I've learned the most. Not to say that I'd seek them out deliberately or anything, but I think it's a mistake to view bad trips as necessarily worthless or necessarily harmful.
I see bad as confrontations with one's psyche, with one's subconscious, with things one has been denying or avoiding in ordinary life. To the extent you consciously face your demons on a bad trip and try to learn from it, they can be of great and profound value. For me it has been, as they say, like years of therapy compressed in to hours. Both the good and bad trips have also radically changed my understanding the world and the horizon of what I consider possible.
As much as I'd like to, I don't think I can in good conscience recommend that everyone take psychedelics, as everyone is different, everyone reacts differently, and people at different stages of their lives are ready or not ready for certain experiences. Especially at the higher doses, it could be a very profound, life-changing event -- for better or worse.
I would definitely treat it with the highest respect if one ever considers trying it. Those who decide to would be wise to prepare thoroughly, find out as much as they can, have an experienced sitter they trust, do it in a safe, supportive setting and with a healthy frame of mind where they have no other obligations at least for that day and the day after. Best of luck.