Just a random idea, for stories or rpg systems:

“Magic” is just using “Bugs” (errors, inconsistencies, etc.) in creation (which may or may not be an actual simulation, running on some form of “machine”).

This implies that “Magic” is basically random. For example, doing a specific action under certain specific conditions for a certain amount of time, might make a cake appear out of thin air. But while neat, this doesn't help you at all to find other magic “spells”, because there is no logic behind it, just a bug in the “algorithm” of cake creation. So any magic “system” is automatically wrong, there really is no connection between different spells - but people will of course continue to search for them. (Of course, there might be two “spells” that are based around the same bug, but since no one has access to the bug itself, just the effects, it's hard to know for sure).

Additionally, another idea is that by exploiting the bug too much, you risk that it gets fixed. The more a bug is exploited, the higher the chance it gets fixed. Thus people will also not want to “teach” magic or write it down, because the more people know, the higher the chance that it stops working. Secrecy is an integral part of magic this way and people try to hoard spells, because every spell is very valuable.