This was horrible advice for me and caused my a lot of grief for many years wondering why I still couldn't focus.
Nothing against Andrej, part of the reason I hate this advice is that this is very common advice for what your environment should look like. This was advice given by study workshops at my college. I'm sure this works for a decent chunk of the student population.
Quiet places cause me to mentally drift into outer space and I just zone out.
You know what is a great environment? Semi-busy coffee shops + headphones + instrumental music. I'm able to consistently lock in for 4-5 hours. When I go back to my "nice quiet home environment" I get distracted immediately and refocusing is super hard.
Like I said, this is standard advice that works for a portion of the population, but I think this makes a ton of other people in the same boat as me feel lazy/discouraged/unfocused/stupid losers when in reality "nice quiet places" might not work for them.