Well it was a ridiculously dogmatic statement! "Don't believe anything". Really?
Not really. Most circuits behave similarly (or indistinguishably) with a range of tolerances on the components, and that includes physical and simulated circuits.
Circuit simulation is an extremely solid science, and in the vast majority of cases it produces useful, accurate results. Furthermore, tools like Monte Carlo analysis exercise corner cases to see if any combination of tolerances produce aberrant behaviour, something impractical with physical circuits of any complexity. Simulation allows you to analyse behaviours that would take hours or days using physical test equipment. Simulation is a valuable tool used extensively throughout the electronics industry.
So when you say "I dont believe anything a computer may tell me about cirucit values" then yes, you are being ridiculous. Whatever you do, don't say that in a job interview.