hmmm... I'll go over a list of my addictions and say which have effected me the most.
weed - probably, overall, the most. It was a lot worse during middle/high school days but I can still tell the laziness of not wanting to do anything.
acid - never had a problem with substancial use
shrooms - as some others have said, I also have felt like my life is shit for a few days... yet this is only with field mushrooms, hydroponic/homegrown usually treats me just nice.
meth - one of the worst, i only did this for about a month, but it started out as a gram a day, which then turned into an 8ball a day, eventually getting worse. I will never do this drug again, my personality is way too addicting.
coke-nothing really at all except I'm irritable after a binge.
wippits - makes me stupid forever!!! lol
Livestock - been the last few years, this last one great. I went with 10 hits of acid, 45 mg 2ci, two 8balls of yizo (between myself and 3 other people), 2 cases of beer, 1 bottle of jack, i brought an oz of nugs, while the rest of the people together combined us over a qp for the camper, and lastly, a cracker and over 250 whippits. Let me tell you when i went to sleep on the way home, i didnt know if I was waking back up. Combining these was horrible after 3 days of not sleeping, not doing this again. Next livestock it's all acid/shrooms and coke for me!