Do you drink coffee or caffeinated soda? Also Modafinil by itself doesn't seem to cause any health problems, so I'm not sure what you're getting at there. The impure Adrafinil can cause liver problems though. I'd agree that a drug that gave work benefits but resulted in brain damage 2 years later isn't worth it, but let's be specific when talking about what health risks are around for particular chemicals, diets, and chairs/no chairs.
My own experience with Modafinil is that it lets me focus intently on one or a handful of things for longer periods of time, but doesn't give me much if any boost in willpower to pick, so I rely on putting myself in the right environment where there's only a few options to pick from.
In fact, I don't, and precisely for this reason. Caffeine addictions seem to be just as bad to me.
Instead, I sleep more (enough so I don't have to use an alarm) and strive to cut unnecessary things from my life to save time. For example, I know it's a little cliche, but people survived without TV until 50 or 60 years ago. I got rid of my TV, and it saved me a lot of time.
Do you eat sugary foods? Fatty foods? Ingesting sugar and fat causes your brain to release dopamine. Without this mind-altering biochemistry, people wouldn't be nearly as compelled to eat a piece of a chocolate cake or a piece of bacon.
(Note: dopamine reabsorption is also slowed by caffeine, which is why it improves your mood.)
My point is not to be pedantic, it's to say that no matter what you're ingesting, you're altering your mood. While I'd obviously agree that becoming addicted to mood-altering substances isn't a good thing, I think that (like sugar and fat) they can be used responsibly.
My own experience with Modafinil is that it lets me focus intently on one or a handful of things for longer periods of time, but doesn't give me much if any boost in willpower to pick, so I rely on putting myself in the right environment where there's only a few options to pick from.