@roger,
For me, it was things that required dexterity, or maybe more exactly being able to see things spatially.
With the shoelace thing, I would watch someone over and over do it, and could not comprehend how putting something "there" then moving it "here" resulted in "this".
hmmmm....thinking about it, I also had/have a problem with flow when learning something. The bike for instance. Today I realized I wanted/needed to master each separate component. Of course you can't do that when it's all being balanced and is moving forward at the same time.
Something else I was a loser at, and related...cheerleading.
Not that I wanted to be a cheerleader. There's that time when all the girls decide learning cheers was cool and fun, but no way could I do it.
I'd watch others do steps and hand gestures, jumps and such, and someone would say "put this in the middle, right after this" adding some other move. I still can't see how they would just effortlessly merge it in.
I would painstakingly learn to lift my arms, then put one foot forward....then would be challenged by now lowering my right arm to 90 degrees.
When the forth step of hopping onto the other foot was added, I'd totally forget to lift my arms.
