(I can't say this is the MOST important thing I've found in life, but this is pretty huge...)
For the longest time, I always thought going along with the group was being a good friend, and anytime someone said "What do you want to do?" I'd shrug and say "I'm good for whatever" was always a good thing to do.
I learned that that was taking the easy way out. It's actually being a good friend to choose an activity, plan it, show interest in people and encourage them to participate, and present it to the friend group and give people the option of saying "Yes" or "No" and working through times, people's availability and prices and such. There's no perfect activity planning where it's 100% perfect. What's actually the good righteous process is putting all the details together as best you can, putting it out there, letting everyone shoot holes in it, and iterate through the process, adjusting times, schedules, prices, until everyone can make it as best they can.
I had my own social insecurities through high school and didn't have a close friend group until into my 20's, so it took me awhile to figure this out. I've since organized some get-togethers, getting a bunch of friends together, sending emails, bringing in who needs to be brought in, keeping track, sending updates, and it's a worthwhile endeavor.
I used to resent the planners, resenting being pressured to make decisions, hated being put on the spot with what day was good or bad, what I could afford, but I always appreciated the activity, movie, dinner, whatever after the fact. Realizing that I always put it on other people to tell me what to do and coming to terms with the fact that my friends liked me and wanted to see me and were willing to work through the plans so I could participate.