I'm a huge Beatles fan, and whether or not I would have found any of them to be insufferable gits in real life is kind of irrelevant to me at least. I wasn't as enamored of his later solo work, but still, a perfect example of the old cliche "a senseless waste of human life".
Add to that list Terry Kath, who died just over 30 years ago, accidentally by his own hand. Alcohol and guns make for a dangerous mix, from the almost comical (a certain former VP) to the (more commonly) tragic. One of the most underrated and underappreciated guitarists around, particularly ironic because his band was so well known and popular. Chicago Transit Authority had guitar work on it that seems far and above most of the guitar playing going on at the end of the sixties. I love his taste, the fire and soul of Hendrix with the complexity and nuance of a jazzer.
One of the saddest moments on youtube is a taped performance of "If You Leave Me Now" from 1977 with the video panning briefly over to Kath, subbing on bass (backing for Cetera on guitar and lead vocals). The man just looked depressed and I could hardly blame him, as Chicago devolved into its commercial pop juggernaught phase of the late 70s and 80s.