Can someone explain to me why I can take this easy little chart

out of a cuff down sock pattern, drop it into a toe up sock pattern, use another pattern for various bits with relative ease. Btw, I’m not good at socks.

And yet a simple shawl with this easy little chart (Fall Leaves Shawl, Spin Off Magazine)

with no other modifications has taken me down a three year trail of painful woe, frustration, and heartache?
Even though I’ve just finished the 7th 16 row repeat, I don’t dare say it’s going well. But I can safely say that I like how it looks.

Can’t I?
Dear Keeper of the Knitting Mysteries, may I?