So he was re-striping, carefully following the old lines and matching the stencils that were there. (Matching the stencils was easy, we still have the same stencils we used when we painted it a couple of years ago when it was new.)
He was about to paint the center line and left and right turn arrows at the driveway that exits to the busy street. Now, it's great to have two outbound lanes so that the drivers attempting a left turn from the lot don't hold up the ones turning right. On a busy street, you usually have to wait longer for a left turn, since traffic in both directions needs to be clear. So two clearly marked exit lanes are a good thing.
But thankfully, Rob noticed that something had changed since we were there last. The city had installed a raised center median in the busy street. This means that the left turn lane now leads into oblivion.
He noticed this before he painted the exit lanes and was able to change to a single right turn lane.
Moral of the story - it's good to be focused on the job at hand, but first, take your eyes off the lot and look at the big picture.