>>30314706They teach us in game design to find shit that works and incorporate it into our designs in ways that improves the overall experience. Obviously we're not supposed to just rip off everyone wholesale, but the goal is to improve and refine designs in pursuit of that "perfect state" of a game.
If you see somebody with rubber tires on their car and you see that's working much better than the stone wheels you've had for 30 years, you trade up for the better tires.
So really, from a game design perspective, unless you literally clone something 1:1 from somebody else, there's no problem in taking notes out of somebody else's book. In fact, it's encouraged.