SWIM LOVES diphenhydramine, he gets rarely any bad effects from it, and enjoys it every time, but there is always one awful moment in every trip. It's the same every time, and it's horrible for a few seconds, but it passes and he gets back to enjoying himself.
Every single time he's done he's done this drug, he's been alone, and every time, he becomes convinced that he's in a room full of 4-8 friendly people, laughing and joking, being friendly, and he gets a sense that these people are wonderful, and being with these friends is all he could ever wish for. They're never having a conversation that directly includes him, but he's loving just sitting there and enjoying their company, but then (and this is how it happens every time) one of them will say "hey, what do you think?" or "do you ever think that?"
At the point where one of them tries to include SWIM in the conversation, he realises that they're not real, and feels awful that he's alone, but is sure that he can bring them back somehow, if he tries hard enough. A few times SWIM has found himself walking slowly around the house calling "hello?" and getting no reply, and after a few minutes, he's resigned to the fact that he's a alone. At this point a feeling of unbreabale lonliness comes over him, even if he's been with friends all day up untill a few hours ago, and he's not actually lonely in his life.
This feeling is so awful, but after a while, he tries to make logic take over, and after a few moments, he's forgotten all about it and is playing with pieces of imaginary string and curling them around his fingers again.
This only happens to him once every trip, but it happens about 4/5 times he does diphenhydramine, it's almost an inevitability, but it's still worth it in his opinion. SWIM can see that lots of people wouldn't like diphenhydramine if these things happened to them more often, because they really har horrible.