It's important to MAKE TIME FOR FRIENDS and things you enjoy doing. Because after all, you do, and you will, ONLY LIFE ONCE, lol #yolo.
But seriously, when you look back on your school times at McMaster, you will not have as many good, fond memories. So yes, as everyone stated, even if it's just simple coffee, or bonding over studying, or working out with a friend, or grabbing a quick lunch, that still counts as socialization!
I hope you find the time to engage in social activities, as it keeps your brain active and engaged. I know for me, I can't go without a few hours socializing, because my mind just needs a break from studying and reading that I just need some fresh conversation!