Weird experience - took my GMC truck to get a tune...

Weird experience - took my GMC truck to get a tune-up; the little high-strung bald guy that checked me in (general manager?) put me on edge. Very uptight, awkward guy -aggressive sales pitch. Building was cinderblock warehouse housing Cadillacs, super strange. Walk in to the service counter: Emily, a teenage girl with no obvious knowledge of the automotive industry is trying to explain to me what I need done with my vehicle and the time frame it will take. Other two guys sitting at the front seemed as inept as she did. Basically, at this point, I'm assuming that everyone that will be quoting and looking at my vehicle has no damn idea what they are doing. I of course, politely declined. NO THANK YOU. Heading to CNS.