Drug taking can become a way of life, most people i know have been heavy users of drugs some can take it or leave it, for me i can stop for ages then suddenly need to have something to use all the time.
Boredom is a huge factor man i mean at 18 i started clubbing back in 98 and got mental on e's and speed lovin the music then got introduced to mr brownstone and that was it i went from a social chameleon to a boring smacked up fuck but that was my thing, until i'd tried the down i didn't know that was my favorite and nothing will ever live up to it. For 4 years,that was it then i saw my dad in bits crying cos he found out i was on the gear and i had 2 choices, the brown or the family and life, no contest, i chose the latter and it was the hardest thing to do ever but it NEVER leaves you EVER. So i became a big drinker, cos i couldn't be normal joe.
So sobriety ain't for me either and if you look closely at most folks around you say on the bus or in the pub, in the street, they don't either.