If you smoke weed on your come-down, its not a big deal......I find the come-down from coke the worst feeling i have ever had in the world, and that's why I will never do it again. Come-down from e, i get up early, and get shit done....plus music still sounds better, so you pop your headphones in and go shopping or something.
But like any drug, its bad for you, but not as bad as anything you guys have said so far....
If you drink water, don't overheat, and simply don't overdo it, and are generally smart about it, you arent going to get many bad side effects from occasional use.
That being said, if you get a bad pill, or overdo it, it can get serious, just like most other drugs....