CydKnight
Explorer
It is a game and we should play it for it's enjoyment. I find it interesting that there are many aspects about this game, particular for a DM, that many feel is work that they shouldn't have to do. Some reluctantly do it anyway because they feel it in some way enhances the game while others will simply skip it or make something up that requires either no work or less work. These approaches aren't necessarily wrong as long as you understand how it effects your game and your players. However, I personally find that the more time I spend preparing, the more enjoyable and smooth my games tend to be and I do for the most part enjoy all aspects of that preparation.My point is that I enjoy that part - that is fun for me. You call it work, I call it creative engagement. It is what I like do, so why would I skip it.
If I want I can, and sometimes do, simply make a monster on the fly. My PCs are always doing the unexpected, so I have to do this fairly often. However, I personally enjoy making monsters and do it when I am not evening playing in a group (like now).