I also use speed a lot. I love the up feeling it gives me and how it allows me to get so much stuff done. As a bipolar, it also induces hypomania for me which is always nice.

When I come off of it, I use caffeine and ginseng as substitutes. Although they are not nearly as strong, they still give me a decent buzz and up feeling. I now reserve amphetamines and methylphenidates for exam study. Another thing that gets me to limit use is thinking about how I do not want a tolerance to develop (because I am cheap). This is why I take frequent drug holidays.