What a fun thread... my adage is "you can admire the dust, just please don't write in it!" Momma had a cross-stitch piece reading, "Dust is a protective covering for furniture!" and yes, we collect dust and dog hair...
MY collections are elephants (DH and I love elephants, and have too many... have slowed down that collection), and quilt patterns (I'll never never EVER make all the quilts for which I have patterns...). I'm thinking I'd like to collect thimbles, too... I have an old printers drawer that would hold a collection of thimbles. It's not very original, but we collect what we love, don't we....