Marius,
When I have a legal issue I ask a lawyer, a medical issue a doctor. Problem with the Bakkie a mechanic. A question about hunting I find an older wiser PH.
It's just common sense for me
That's fine when you seek out that advice. How about if you were just checking the air in your tires and the mechanic jumps in with opinions about what size, tread and inflation pressure you should be running, based on what the average guy needs. Are you still cheerful, or do you consider pointing out that it isn't your first truck, or tires and what you're doing has got you this far?