I noticed this recently when I was trying to define a note-taking syntax for my math classes. I thought it would be smart to use := for definitions and = for equality, but then I was frustrated when = didn't always mean equals in the same way, and some things didn't really fit into either category. I ended up just giving up and switching back to abusing = in all situations. I think math has a really cool human aspect, it's very rigorous but also relies on the fact that your notes/proofs/whatevers are going to be read by a person.