In contrast, I, personally, have run into programming/design problems where monoids or semigroups seemed to be the correct level of abstraction to work at. Peop

In contrast, I, personally, have run into programming/design problems where monoids or semigroups seemed to be the correct level of abstraction to work at. People aren't appropriating language and concepts from algebra/category theory for no reason (well, perhaps some are), they're doing so because they find them to be useful tools when building and thinking about systems.