most people do drugs because those drugs make them feel good
i think using drugs when you have to think about big things can be helpful. some drugs remove your ego so you can think about things without yourself getting in the way. weed not so much.
i smoke weed because it makes me feel good and makes things you usually do without weed more fun like movies and sex. thats about it. i'm even about to scale back my smoking a little bit because i'm getting a decent job that i am actually qualified for and don't want to lose it. they arent and will not drug screen me, but i know that if i smoke a gram or so every day like i'm used to, i'm just out of it, lazy, unmotivated and usually sleepy... not very conducive to doing well at work.