If you're on the machines, don't drop them at the end of your cycle. If you can't control them, see above.......
If you're doing dead lifts, don't drop them just to make the rest of the gym think you're a strong guy. You ease them down to get the most out of the exercise...........
If you are so self absorbed in your workout that you don't give a rat's ass about those around you, drop your weights at the back of the gym, not directly behind some person working out in front of you.......
I'm hoping for the day where I witness some muscle head doing bench presses after totally pissing off the rest of the gym with his dropping of the weights, and seeing some guy step up and add his body weight to the bar as the muscle head is doing his final rep............
I dropped a dumbbell on my toe 8 years ago and broke it. Had the other side not hit the ground first, I could have lost a toe.