It can be frustrating, but if you aren't a regular patron who knows "the boys" and can "chew the fat", your work may not get the attention you were thinking was equally doled out to everyone who walks through the door. That may not seem fair, but it seems more common in smaller service industries that are dependent on those relationships with regular customers to provide steady work.
Also, not that I'm saying this happened, but if you drop off a saw, and the shop says "we're a little busy right now, when do you need it by?" And you respond "oh, it isn't that important, whenever you get to it." I wouldn't doubt that it gets put in a milk crate, on a bench out of the way, or in a box, away on a shelf, and forgotten about while a million and one things will take precedence over it. If 6 months go by and you walk through the door and get upset that the work hasn't been done yet, there isn't much that can be done at that point.
Hindsight being 20/20, when you drop a work request off tell the shop a specific time you need something by, within reason, and call ahead on said date if you haven't heard from them. If they say it hasn't been completed, remind them that you "need" it and they've had ample time. Hopefully they'll get to it right quick, as the squeaky wheel gets oil.
Also, of the shop completes your work on time, go pick it up immediately. There's little worse in the shop's mind than a customer who screams they need some work done in an emergency, and they rush the job into the queue, call the customer to come pick it up, and the customer takes his sweet time of a couple days to come get it.
Lastly, always have a positive attitude. Service is a thankless job, and nobody wants to deal with an angry S.O.B. I'm sure they're as happy that you're moving on to another shop as you are to be rid of them.