I agree. Any adviser that judges your capabilities based on how long you spend in the lab is a fool. But I think that in cases similar to the original author's

I agree. Any adviser that judges your capabilities based on how long you spend in the lab is a fool. But I think that in cases similar to the original author's, the student incorrectly perceives the pressure on him to be to spend more time in the lab and less on other things, whereas it is actually to be more productive and focused. Being dedicated and having outside interests are not mutually exclusive.