It really depends on how your body and mind react to the drug. While I can consume and deal with large amounts of LSD, I can't take a single Wellbutrin without freaking out. Couple hits of weed is same way to a lesser extent. As far as Xanax, all I remember is passing out and waking up feeling like someone beat me with a hammer all night. Amphetamines, I can't get enough of. Coke, never tried it because it sounds like everything I'd love too much.

Different minds and bodies react differently.