Replacing rear brake pads and rotors

[seventieslord]

I just read this whole thread and I'm a little confused. Today I replaced my rear left caliper and the e-brake motor. I had no idea that service mode was a thing. I know I lost a lot of fluid, so when I was done, I opened the bleeder screw, bled the brake line until no more air came out, and filled the master cylinder back up - just like my dad taught me late last century. Everything seems fine.

But clearly I didn't do my research, and took a huge risk here. Lots can go wrong when you don't set the brakes to service mode, apparently. Except nothing went wrong, at all. How did I escape my comeuppance today?