I'm an undergrad student studying physics and math and I will be graduating very soon. I might be going to a PhD program in the US and an MSc program in the UK (in the same field). When I reflect on my undergrad studies, I realized I spent too much time on academics to maintain a decent GPA. However, I didn't spend enough time socializing and communicating with different people. Now I feel like I probably should be more sociable and focus on something else to get prepared for grad school.
My question is how can I switch from the current 'knowledge acquisition mode' to the lifestyle of a post-graduate student? I know in my field, the grad courses (for both programs) will still be intense. I'm worried about whether I'm able to balance academics and social activities. Is it essential to keep a good GPA in a master's program (for future PhD application) and PhD program (for applying internship/summer schools, etc)?
Thanks for the help and advice :)