Obvious stuff that you only realized recently

Stormtroper

I only realized recently that "alphabet" comes from "alpha" and "beta".

I only learned recently that the "rational" in rational numbers comes from the word "ratio" (i.e. what they are), not from being reasonable or anything.

I only realized recently that the magnetic pole in the northern hemisphere is, in fact, the southern pole.

glennmagusharvey

In TF2, having attack classes switch to engineer during setup can greatly speed up the pace at which the main engineer(s) set up and upgrade their buildings.  They can't place buildings, obviously, but they can each contribute a full upgrade (200 metal) to any building.

And now I'm thinking:
* Bonus points if they have the Eureka Effect, which lets them follow the main engie to where the sentry/dispenser/exit is and then upgrade that and then teleport back to spawn very quickly to restock and go where the main engie is going next.  Main engie only need to pick up enough metal to put down another building.
* During a match, it may be possible to switch to engie briefly, take a tele to the front lines, and help upgrade another engie's buildings.  Let's call this playstyle the Supplemental Engineer (to differentiate it from the Turtle Engineer and the Roamin' Engineer).