"Sit in bed all day" maybe isn't the best way to describe the problem with such a drug. "Never change anything in your life" might be better. People don't like change, and they generally only make serious life changes when they're unhappy with the way their lives are going currently. If you're never unhappy, you'll never change anything.
The negative consequence there is that often times we don't learn about ourselves until we attempt to make such a change. If you hate debugging Java, and you can take a pill that makes you not mind it, you might never discover that you could actually be a much better Ruby programmer than you ever were a Java programmer -- or that you really were never cut out to be a programmer at all and should pursue something totally different. You'd just chug along debugging Java your whole life and never realizing your full potential.
The negative consequence there is that often times we don't learn about ourselves until we attempt to make such a change. If you hate debugging Java, and you can take a pill that makes you not mind it, you might never discover that you could actually be a much better Ruby programmer than you ever were a Java programmer -- or that you really were never cut out to be a programmer at all and should pursue something totally different. You'd just chug along debugging Java your whole life and never realizing your full potential.