I own a motorcycle shop so Yeah, I have a couple that make my work much quicker which equals more productive.
My Bosch 10.8v Impactor is awesome. it's great for running down bolts quickly, but it doesn't have a whole lot of power so I don't have to worry about over torquing. I can go back and toque properly by hand.
works great for removing small fasteners as well for teardown.
My 3/8" impact probably gets more use than anything. Great for tear downs. etc. also good for running down larger bolts etc. quickly. It does make enough torque to break a smaller fastener though. so Have to be a little more cautious.
my number 1 tool though is probably my Mac. It has all of the service manuals on it, parts diagrams, garage journal

and of course streams music all day looooong.