Mediocre employees = showing up on time, being well-meaning, but making very slow progress and many mistakes due to a lack of, to be honest, intelligence. Not r

Mediocre employees = showing up on time, being well-meaning, but making very slow progress and many mistakes due to a lack of, to be honest, intelligence. Not really understanding why those mistakes are a problem even after receiving an explanation and coaching. Do you think that's a death sentence?