Too simple for a check is far more likely than impossible IME.
If you make #2 the first step, you only need to make one check (too simple = yes, stop) the vast majority of the time, vs two checks (impossible = no, too simple = yes, stop).
I find that simple actions:
"I walk to the bar and order another ale."
are far more common than impossible:
"I walk to the End of Time and order a Pangalactic Gargleblaster."
Admittedly, this might not be true if the players constantly want to do impossible things, but I can't imagine how that would happen with regularity unless the players were getting their jollies from messing with the GM.
All that said, the question was mainly poking fun at myself. I write software for a living, so that sort of analysis is literally part of my day-to-day. It was the first thing that popped in my head when I read it, which I found amusing, so I figured I'd share.