I used to believe this until I started following a math teacher on YouTube. He makes me realise how much of our time was wasted at school with empty formulas without ever actually clearly touching on their relevance in the real world...

Not sure I fully agree with that. A lot of students feel like these things are irrelevant to the real world, but it's only because they can't see the relevance yet.

Sometimes, the relevance isn't taught till later. Actually, some of the relevant applications would be too difficult to them, so imagine complaining that the easy thing is irrelevant when you can't even do it; and would get destroyed by the real world relevant stuff.