Okay, this one is for real.
I won't purport to be an expert on this subject. But I have noticed a distinct difference between the nature of the quests in my last campaign and the one I am currently playing in.
When we played Engines & Empires, our quest to stop the evil Baron MacKenzie was an 'opt-in' quest. By that, I mean that there wasn't anything forcing us to go on this quest. We started at level one as a group of lawfully aligned adventurers that stumbled upon an evil sorcerer's plot to find an ancient sword. As we continued on our adventures, we discovered more about the plot and decided to take matters into our own hands. Players came and went with little to no issue (more an indictment on the players and not the adventure). By the time the queen of Avalon charged us with stopping MacKenzie, we were already level 6 and three steps ahead of her. We pretty much went to the queen for the rewards we knew she would give us for doing what we were already going to do. It was a win-win situation.
Retro Phaze is a completely different scenario. For starters, there isn't anything resembling a hero in our ragtag bunch. We were a bunch of people in the wrong place at the wrong time who are now framed for a crime we didn't commit. I guess ideally we would come together as some part of a heroic galactic rebellion or the A-Team in Spaaaaaace! Two sessions in, and I have no idea how I'm going to play my character in this campaign. This shouldn't be a problem, I should be able to figure out what my niche in this campaign and carve it out and thrive. The problem right now is, I haven't figured out what it will be. I have an idea, but I can see another player stepping on my toes as I try to develop it. It's going to be a challenge that I hope I am up to.