I think that red-k Clark did a lot of things Clark wanted to do and the red-k was just a cop-out. No one did anything about it. He was just able to return the leftover money and go home.

I don’t think he thought about the crime stuff when he took it. He probably thought he wouldn’t succumb to that

He didn’t think of any of the ramifications

Okay smart- cause when Alicia poisons him he tells his mom he didn't have choices while on Red-K it's like a zombie drug.

He totally and utterly betrayed his friendship to Lex when Lex was imprisoned in Bellevue and had his memory wiped. And more generally, Clark is the ultimate gaslighter. There's a big difference between having a secret, and making people doubt themselves and question their own sanity. Clark is the worst of friends to everyone he knows. He's a truly nasty piece of work.