Forgive me but this is a case of the blind judging the blind. I never go into LBS because what you describe is what you get. Getting hosed or poor workmanship or both is part of the landscape...not unlike car dealerships btw only on a broader scale. You may think you can trust people but their livelihood depends on selling product. By contrast, engineering is my calling so I am much too discriminating to have a LBS tune or even touch my bikes. You are in a box of sorts. You are mechanical enough to know your bike is out of adjustment but not enough to know how to adjust it. If you ride in a group or a club there is likely an engineer or a mechanic that may adjust your bike for free...maybe even change a part or two from time to time. I try to help out my friends because helping others always gives back manifold friendships and other aspects of fulfillment. Try to seek out such an individual. I believe mechanical aptitude is largely etched in the DNA. Kind of like doing math. Some can do math and even calculus in high school without opening a book. Some can draw. Some can play music naturally etc. Good Luck if you are beholden to a LBS where they have kids working in there on your bike who only know enough to be dangerous. I can't tell you how many bikes I have fixed and tuned after the owner just got it back from a LBS and it didn't shift properly.