Me too, OP, I’ve had several Hermes parcels for the things I’m planning to make. And there’s a vast stash in the spare room - colours/yarns I have no plans for - yet. Though I did use quite a lot of rather nasty pink (should have returned it but didn’t) to make the ‘knitted breasts’ our local hospital was asking for, for breastfeeding advisors to use in demonstrations! A fair bit of sundry colours has gone into twiddle muffs, for dementia patients, too.
As for ancient supplies, a couple of years ago I dug out some pastel shaded yarn I bought to make a cardigan for a dd, then maybe 8. Why I never made it I don’t know, probably I found the pattern too complicated. I don’t think I even started it.At any rate, when that same dd was 38 (!) I finally used at least some of it to make dolls’ clothes for little Dgd.
In the past I’ve had a lot of other UFOs, always because I found the pattern too complicated or difficult to follow. Nowadays I only embark on anything I know I have a reasonable chance of finishing.