Could you explain this statement, in layman's terms? "Believe it or not, too
many grounds can often result in more problems than insufficient grounds."
It's new to me. I always thought that electricity simply found the path of
least resistance, and so doubling grounds couldn't have a bad effect. Is
that wrong?

In my own case, with a 1.9 (one-wire sensor) I didn't trust the OE sensor
ground through the rusty 23-year-old exhaust, and so installed a solid
copper wire from the sensor body to an engine ground point. I also read
somewhere that head gasket problems might be caused by insufficient grounds,
with electrolysis created by the flow of electricity from the ground point
on heads through  to the engine case. To remedy this I installed my own
"web" of copper ground wires to points on  both heads, the case, the frame,
etc.

Can these "remedies" cause problems?

Geza