When you break down anything into its subtasks there's basically nothing that anyone wants to do. Sometimes the ends help justify the means too.
You're claiming that any subtask that is unappealing automatically makes you not want to do the whole thing. Which is silly.
What makes you think that?
Do you think nobody wants to write and debug code, or tend to plants, or write books, day in day out?
I always wanted to program games. I programmed games as a hobby. When I graduated university there were no gamedev jobs in my region, so I went to work at Boring B2B java company.
After a while I moved to a bigger city and I started having friends who work in gamedev. They told me about crunch, bad salaries etc. I decided to keep doing Boring B2B stuff. But I went to a few job interviews in gamedev companies.
Every time the questions on the interviews were FUN. Like doing 3d math, some low level C, writing a collision detection function or simple pathfinding.
Just solving these problems made me giddy.
Maybe it's the nostalgia for the time I've learned these things as a teenager with no stress, or maybe it's just that it's something completely different to what I'm doing normally - but I felt great during these interviews.
But I'd have to get a huge salary cut and abandon work-life balance and I'm too old for this.
TL;DR: I think there's a lot of value actually looking at day-to-day problems you need to solve in your dream job, even if you decide it's not for you for different reasons.