1. Having to compress level data, to shave a few hundred kilobytes of data that can't quite fit into the memory of the 3DS without it crashing, but then it being perfectly happy to have about 7Mb of audio crammed in.

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2. When you have to look back at your "Pixelart to 3D Printer STL" tool that you wrote just a few months ago, and wonder why on earth you chose to use Blitz3D to do it, when you could've used your new 2018 C++ framework.

3. That the hastily cobbled together code for that tool isn't even vaguely optimised, and that you're going to have to spend most of today either fixing it up, or deciding to do that complete re-write in C++ instead.

4. Menus.. I HATE Menus!!!

5...