Very simply, drugs make you feel awesome. That's about all there is to it. The problem comes in when you want to maintain the level of awesome ... and can't.

Very simply, drugs make you feel awesome. That's about all there is to it. The problem comes in when you want to maintain the level of awesome ... and can't. That's when the detrimental side effects hit. You can be quite a high functioning, normal member of society with a drug habit. As long as you can pay for it, and as long as it doesn't interfere in the aspects of your life you don't want it to, one can make a rational case for continuing drug use. Think about coffee. It's great. It makes you feel great. It's socially acceptable. It's also highly addictive, and the withdrawal symptoms can be nightmarish for some people. But it's not viewed as a bad drug.