I feel you. The first spring we lived here my wife was so excited to plant some roses. Come around to spring two and she's concerned one rose grew a bunch and another did not at all. She went digging around and found a piece of concrete probably as large as my head that was just a smidge deeper than she dig out for the rose. With how deep it was buried I figured it was from the foundation work and they just left it.
Not as bad as rocks in the ground but years after living here I was trying to find a certain faucet wrench I was hoping the contractors left since the original kitchen faucet used a non-standard nut. Went looking in the water heater closest where they had left a bunch of extra tiles and some other random things, moved them out of the way and found several empty beer cans. I shutter to think what is probably underneath the blown insulation in the attic considering the other trash left around.