you can not build up a tolerance to THC. this was a myth propagated during "reefer madness". the government wanted to make weed seem more like other "harder" drugs (coke heroine). the reason you can not develop a tolerance is because while THC messes with your cannibinoid receptors on brain cells it does not damage them like other drugs. this is why it is not physically addicting and why you cannot get a tolerance. the reason some people continue to believe this is because a marijuana high has alot to do with what the person taking the drug believes will happen. If you think you will get horny, you will. if you think you will get hyper, you will. the reason that you get a better high after a few days without doobage is because A. you think you will B. you have time for your body to flush out residual THC and therefore start with a clean slate & C. because you probably smoke more than you otherwise would, if you are an everyday smoker and you stop for 5 days. you would logically have 5 times more reefer than any other day. more herb = more chonging