Dumb

I can't recall the expression for just learning something new that everyone else probably already knows, but I had that occur to me today.  I was washing my car, and I realized that I had a couple of exterior lights on the front of my car that I didn't know what they were for.  They were below the main headlights, and I don't think I'd ever seen them on.  Do they even work?  Well after playing around with the different lighting settings from the driver's seat, and then realizing that didn't work when the engine wasn't switched on, I discovered that these lights did indeed work and that they are the fog lights.  D'uh.  I always thought the fog light was an extra bright red light on the rear of a car - it never crossed my mind that it could be extra lights on the front of a car.  If visibility is poor, I would only think of using high beams.  So I guessed I learnt something new today.  And I feel quite stupid.