If I had to do it over, I think my "first date" would be buying an entertainment stand at Ikea and assembling and finishing it. Or a desk. Something complicated, many pieces, tools required and assembly in five hours or so.
At that point, if the five hours were finished, the desk assembled, no broken parts - especially on the humans, then I would consider a second date.
Start with a challenge, a goal and a plan. Each relationship should begin this way and CONTINUE this way. On a short term basis you would be able to determine if you could communicate well to each other and understand the directions together. You would determine if someone is a hands on person or a built-in-store person. You would learn to compromise by finishing it in a color you both like. And you might learn a lot about someone' work ethics "152 pieces?? Forget it! You can build this yourself!"
On the longer term, you need a plan in any serious relationship, you need to be able to recognize broken parts and the ability to do some assembly along the way. Pieces will break, problems will happen but you don't throw out the desk because a handle is loose. People should pay more attention to broken parts in their relationships, because it only takes a little effort to save something but it takes so much more energy to start over and build again.
And a blueprint - seriously! You don't get to where you want to be by waiting for it to happen. If you want to do more as a couple, find more to do together. If you want to be happier, find ways to make each other happy. You can't just expect peaches and roses, you have to plant them.
And of course you don't get to the 15th piece of a puzzle and then put it back in the box. You can't expect this out of a relationship either. And you're not in it alone. That 15th piece might seem like a hurdle you can never get over, a problem with no solution, but your partner may see a far simpler solution. An easy fix. A new pair of eyes can solve many problems, so don't forget that they are there for you, and ask for their input.
On the other hand, if you get to the end of the project and you find leftover parts, wobbly brackets and no paint at all because the two of you can't agree... Maybe it's best to rethink that second date.