As Bob Pease of National Semiconductor said (in a different context,
also having to do with ground impedance): "You may be able to trust
your friends. If you're very fortunate, you may be able to trust your
government. You cannot trust your ground."

A very smart guy.

My rule for current: "Always put it back where you got it from."
If you let it find it's own way home, it will usually make a mess.