Stupid, useless ones mostly. Like if I am at a pharmacy, I might think about how easy it would be to go get some over-the-counter codeine and how that really wouldn't be so bad because I wouldn't be totally wrecked. It would just be a pleasant little jolt and I can still function and it's no big deal (I lie to myself until I think it through).
I don't seriously think about booze and druggy drugs because I know exactly where that goes. I am almost immediately impaired and stupid and unable to work/drive/function socially. And I don't stop. I know that. I have proven that to myself so many times that I am convinced to the core.
But I can sometimes lie to myself about stupid, useless drugs.