Just because Doug lives on his own little island, is retired, and has nothing better to do...It's the cabin fever.
At least, for most of us it's cabin fever.
Some (esp. the multi-personality troll) have always been that way & nothing will change them.
You'd think a man of his age would act more civil rather a 12 year old who hasn't hit puberty yet?...then again, maybe it is his senility.