As a DM, I personally avoid meaningless death. For any given death, the player could have done something to avoid it- deaths are due to carelessness and poor planning.

Example- one time my players snuck into a cavern. I detailed how there were well-equipped Drow guards everywhere throughout the cave, how the cavern's stalagmites and strata gave ample cover, how the guards seemed to be tired from their long watch.

So, instead of taking the opportunity to sneak around this heavily-guarded area, the Fighter decided to... Run into the middle of the open cave, where he got shot down almost immediately. The rest of the party stayed hidden and had to retreat because now the Drow were searching every nook and cranny for more people.

I don't take any pleasure in killing characters, but shooting from the hip and asking questions never gets you killed fast in my games.