Maybe the best way to look at quickie oil change places like Jiffy Lube is like you look at fast food restaurants: A 4-star restaurant or a good auto shop employs skilled chefs and wait staff, or good, certified, mechanics and techs, and pays commensurately, thus attracting professionals that take pride in their work, and enjoy what they do, for the most part.
A bad quickie oil change place or a fast food restaurant employs the unemployable, regardless of the economic conditions of the area or the general economic climate. They pay badly, the turnover is high, and while there are some good folks that work there, they attract and hire a lot of people that can’t find work elsewhere. As such, their employees are just marking time until they can go home, are probably harried by a manager that is in the unfortunate state of being between a rock and a hard place (upper management that wants results and slackers that want to be left alone and do the minimum), and are likely not much more skilled than their employees–there are no budding executives at the establishments that don’t care.
So basically the same quality of place that screws up your order, or serves you something that’s well past its expiration date, or perhaps has even been spit in out of spite, is working on your car. So you can expect someone that’s smoking weed to just get through their awful day (and perhaps rightfully so) to forget to put your drain plug in, to use the wrong oil, filter, or just generally not care, especially if you’re giving them more flak in their already harrowing life.
I don’t like to seem jaded, but I managed a restaurant for many years, and while I like to think I was not the manager that I describe above, and that I was actually a good person to work for and cared about both my customers and my workers, I saw plenty of both the unemployable and the customer from hell.
I have been an IT professional for over a decade now, and it’s sad to say, but I see the same situation with level-1 Helpdesk employees at companies I’ve worked for, including my current gig. Lather, rinse, repeat.