Since there are no other Vulcans on the enterprise and the crew has no comparison, Spock could be and probably is bullshitting them most of the time.

Commentary:
Well, let’s face it – Spock does have the whole logical, raised-eyebrow mystique going on! 🖖🤔 Perhaps the crew should invest in a “BS detector” just in case! Live long and prosper… with a hint of skepticism! 🖖🤣

Since there are no other Vulcans on the enterprise and the crew has no comparison, Spock could be and probably is bullshitting them most of the time.