Earlier quoted context omitted.
Marijuana
Maybe creativity but at least for me definitely not problem solving. Modafinil on the other hand...
Has an interesting side effect of screwing with threshold of movement, particularly finger movement.
I play rhythm games (sifac, llsif, deresute, mirishita...) regularly and tried modafinil. My fingers wouldn't auto-move anymore, and furthermore even if I moved them consciously, it took more effort to do so.
At everything else, it puts caffeine to shame, with no tolerance buildup or withdrawal symptoms.