Why does Kahneman describe System 2 as a 'lazy controller'?

Answer & explanation

It usually accepts System 1's suggestions without exhaustive scrutiny

System 2 is capable of logical scrutiny but usually accepts many impressions proposed by System 1 without detailed verification. Kahneman describes this as laziness because deliberate checking consumes effort. The result is efficient most of the time, yet a plausible first answer can hide a contradiction that a simple check would reveal.