Same. My favorite mutator was the exploding ammo cases. So much fun to see an enemy run to pick up an ammo box and just shoot it with a pistol blowing it up in his face. That was apretty revolutionary game mechanic 20 years ago. Do any modern games have such a thing?
That volatile ammo mutator was made even more awesome because it actually spawned "shots" of that type, so a plasma pile wouldn't just explode but rather spread various plasma shots around it. The granade one would have the granades bouncing around a bit before exploding. It was so easy for things to go wrong and backfire on you :)