The text editor I use is not smart enough to locate and understand function definitions yet, so I waste a bunch of time going up and down between the definition and where I'm calling the routines.
Until today I had no way to scroll to a definition without moving the cursor. Which meant that each time I jumped to a definition, I had to jump back.
Each day I'd run this through my head "Would I spend more time implementing a scroll-to for markers, than the amount of time I save..?"