Sometimes we don't trust experts - when they try to sell

Today I went for oil change @ Lube express.

The technician behaves like a doctor for my car. He tells me what I should do (meaning choose costlier service package). He warned me that if I don't do as he says, my car might breakdown. I was scared. Sitting inside, while he pulled so many tubes and filled many more liquids, I was wondering is this a good experience ?

Have you ever understood what they to each other
" we got this guy..hmmm $$$ ...let's party..." something to that effect.

I feel that every time I go for oil change, I am advised of so many things that I end up paying a hefty $$. Couple of observations :

1. I am amazed at the complexity of cars (even in this technological age). Do you how many liquids are your car ?( Petrol, injection fluid, oil, wiper fluid ...).

2. The technician knows everything about my car. He changes from being a doctor to a salesman.

3. I sit inside the car, while he does something in the bonnet and below the car.

4. After the session (once I paid big $$) I am always told that now I don't have to worry for long-long time.

5. But then, I get my car looked after while I enjoy my radio.

6. They show me lot of dirty parts out of my car to prove their point.

Do I trust them ? Does it matter if I don't ?

Wouldn't it better if they gave me a one year schedule, with all the costs for each session. That way I would know cost of maintainance. Lube express knows how to train technicians to be salesmen, but still raise lots of suspicion in the way they do their job.

I would love them, if they tell me for a specified $$ per year, they will ensure smooth running of my car. Then I would go back to them :
a. eventhough many others want to do offer me similar service
b. without any discount coupons.