I sometimes play challenges that require doing certain aspirations. I also have some characters complete partial aspirations just to get aspiration points, which might be any aspiration, depending on what's convenient for their lifestyle. I do have some least favorites that I would never play all the way through outside of a challenge.
The worst is Successful Lineage. It takes forever. Since I almost always play on normal lifespan, by the time it's complete, the sim's almost elderly. The reward? You learn things faster . . . as an elder. My elders are past that rush-to-the-top nonsense. If they're learning a new skill, it's as a hobby, not because they want to be the expert yesterday.
I also don't like the Vampire aspirations. I don't like turning lots of my sims into vampires. If I don't want a vampire to suck blood, I give them a supply of plasma packs, that simple. Doesn't need to be a trait.