Because it caused me all kinds of problems and felt like I poisoned myself and had bad after effects for months. I did binge on it though. No other drug has felt so fucking toxic to me, and there is research coming out that points to it being nasty shit, although I don't know how much faith I put in any recreational drug research given that they are all government funded and lying fuckwads. Not to mention mephedrone is both vasioconstrictive (sp?) and inhibitory to the part of the brain that counters that, and it increases heart rate to boot, so it must be fucking horrible for the circulatory system and heart. And it is until recently almost completely unresearched, and has given some people negative health effects mimicking autoimmune disorders, caused peoples knees to turn purple. It made the entire inside of my mouth get blisters in it and all kinds of nasty shit. If there is one drug I wish I never used in my life it is beyond any doubt mephedrone. I also wish I didn't use so many/much disassociatives at such a young age. And I wish I didn't go research chemical crazy for a period of my life where I was tripping like three times a week for months. But that is just some regret over using way too much drugs, I still love to disassociate a lot, and still enjoy research chemicals in general. But mephedrone I wish I never even heard of honestly.