For the last few weeks I've been studying Unreal Development Kit (UDK). The engine is great, and the editor is relatively simple. However, it has certain drawbacks as well, small things really. But it is funny how small things can get you raging.
Just one of these, for example, is that when you want to make an interactive liquid, it's surface can only be a rectangle (FluidSurfaceActor). This issue is quite popular and been discussed on the support forum. It's not a big deal when you know about it: you just find a way around or design your game considering this limitation. But for the first time it really makes you ask: "Why? It's such a small thing, it shouldn't be like that!".
And there are many other small bits like sluggish material editor with no option to create a material somewhere else, Kismet for everything (I am a programmer, I prefer to type commands not to "draw" them), Ctrl+S to subtract geometry...
If the engine hadn't been awesome in the first place, these small issues woudn't bother much. I think it is in a human nature (or in my own nature?): if something is really cool, I want it to be perfect. And it upsets when it's not like that.
I was so moved, so I made a comic!