I tend to pick similar aspirations for my Sims. As in, many of my Sims have been wannabe Chefs, or whatever. I've also not completed many aspirations.
I'm going to mention a kid one: Social Butterfly. It takes forEVER to make a BFF, it seems, plus the social skill seems to be the hardest to raise. The other kid aspirations have been fine.
The very first Sims 4 couple I created had the same aspiration as each other. The male Sim died before completing it, but I managed to do it with the female Sim.