It's Not At All Obvious You Should Neuter Your Dog

Evidence indicates that it does not solve behavioral problems and may make them worse, and it can have extremely bad consequences for their health. It's not that common in many European countries, and is illegal in Norway.
Here's just one link.
I'd bought the "spay and neuter" propaganda, and just happened to think to read up on it before I did it. Very glad I did.
Dunno what the right answer is yet...but pretty sure it isn't entirely obvious.