I'm another one who appreciates what comes on the rocks. Those hydroids in the middle photo may give you trouble if you try to site a coral next to them, but they can be managed (or gotten rid of if you must)---and I have quite a few of those worms (below) too, and enjoy watching them go. Some want only what they've planned, but I like surprises in the rocks, and the only place I draw a firm line is caulerpa weed. If I spot that, I get the rock out and treat it, but all the rest I just enjoy watching.