Mine that I need to stop is Masdevallias. I've tried three and killed them all. I cannot find the happy balance to keep them wet enough, but not so wet that they rot. I'm giving them up and will admire them from afar.
I'm on my second one on some species and really, the ones I'm trying not to kill aren't even difficult...
Very mature decision of you to stop trying to grow them. I wish I had your self restraint.