The following is why I will never take creatine.
Back in my bodybuilding heyday, I knew an ex-Marine bodybuilder named Josh. He naturally put on muscle so fast that he had to ease off his leg routines here and there so his quads wouldn't split his pants wide open. He had one of the most incredibly balanced forms I'd ever seen, reminiscent of a smaller Schwarzenegger. We used to climb dry waterfalls together in Colorado while I gave him advice on his girlfriends.
One day, he announced to me that he was going to supplement with creatine. I gave him a quizzical look and asked him why in the hell he thought he needed that since he already had it so easy in the gym. I think he might have suffered from Muscle Dysmorphia, where a guy is obsessed with being bigger and never feels big enough, sort of like the reverse of anorexia. He said he was a skinny kid growing up although I could never imagine it.
Anyway, I didn't see him in the gym for three months, then he showed up all of a sudden. I did a double take and then stared at him. I almost didn't recognize him. His face was all sunken around the cheeks and eyes, like a corpse, and his skin was actually grey. I'm not joking: grey. All the color was gone, like the life was sucked out of him. His mass wasn't much different but he was missing fat in a way that made him look like an alien. Not one to ignore things, I walked right up to him and asked him what the hell was going on. He dodged the topic a bit but I got it out of him eventually that he had been using creatine.
A few months after that, I saw him again. He appeared normal now, healthy and fit. He thanked me for pointing out how awful he had looked and confessed that nobody else had the guts to tell him to his face except for his girlfriend and I. He said it scared the shit out of him how serious he let it get and he wouldn't do it again. He never told me how much he was taking.
To this day, I can still see his skin. Gives me the willies. I'll never take the stuff.