Something that my Dad said to me when I was younger has stayed with me on into adulthood:
“Go and do a bunch of things, be active, have hobbies, play an instrument, or learn to play a sport. You want to be seen as well-rounded and adaptable. You don’t want to be seen as just an egghead.“
The ideal would be that you are a Renaissance man, where you as a jack-of-all-trades both know a lot and know how to do a lot. Focusing on one thing can throw you out of whack.
I’ll give a general example of focusing too much on one thing.
When I was in Undergrad, my Organic Chemistry class was composed mainly of the Chem majors and with the rest being “Pre-Med/Dentistry/Pharm”. Now the Pre-Med types were very smart (you probably know at least one yourself), studied diligently, and received high marks on the exams (breaking the curve and fucking over the not-ridiculously smart, like me). However, with all the facts and mechanisms that they memorized, they were total shit in the lab.
Theoretically, they should have known exactly what to do in the lab based on their reading.
Practically, they were indecisive and afraid they were doing the wrong thing.