A few years ago, I did three group rides. I had never ridden with a group before, so didn't know what to expect, although I did a little research on basic etiquette beforehand.
The three rides were with the same club, same summer. Bit three different experiences.
The first ride was a very hilly 40 miles. We stopped at the top of each hill to wait for everyone to catch up.
The second ride was 62 miles, and from the beginning the cyclist broke into small groups, including two riders who were leading on their own. I joined them, and took my turn pulling. I slowed momentarily after running a yellow light, thinking maybe they had stopped. At that moment, they both accelerated past. We were facing a stiff headwind, and, although I got close a few times, riding solo I just couldn't get back on their wheel. Ended up riding alone for 50 miles.
The third ride was a flat 40 miles, and we had a large group that stayed together. We were cruising nicely at 22 mph, each pulling for a couple miles. That is, until one rider I guess wanted to be a hero and wouldn't peel off to the back. Problem was he had immediately dropped the pace to 18 mph. Mile after mile after mile, it was excruciating to sit in the middle of the pace line with essentially a resting heart rate.
Back to solo rides for me.