No but seriously, drugs aren't necessarily bad to try, but they're definitely bad to use often. I know from experience. I even know a few stoners who exercise, do well in school, etc. and I still think it's holding them back.
The opportunity cost of doing a drug is not being able to be sober and process emotions while sober. If you do drugs enough, you start to build coping mechanisms for being on that drug, so that when you aren't on it, the coping mechanisms are slightly misaligned. Which just makes you want to do the drug more.
So even if you can handle doing a drug and can function well, you're NOT building sober coping strategies while you're on it. Which basically means you're putting off maturity for later.