a little slow on the uptake

I have known forever that most lace knitting requires a solid or semi-solid yarn so the lacy patterns don't get lost among variegated yarn's color changes. So why did it take this...

and this...


and this...


before I clued in and dug out a semi-solid yarn (dyed by us w/ Kool-Aid) to pair with Knitspot's beautiful Rivolo pattern?