shitting on someone's xmas

Today i took my parnets dog "Charlie" on a Christmas morning walk. We got to the schoolyard where he drops his typical load, so I scooped the pile into a baggie and tossed it into a garbage can. As we came down the last street before our house a family of 5 pulled into the driveway right in front of us. They were dressed real nice, it looked as if they just got back from Christmas mass. They cheerfully wished me a merry christmas! I responded with merry christmas to you, at this point i felt a tug on the leash and to my dismay...
Charlie dropped a steamy pile of crap in their front yard as stood feet away. The christmas cheer seemed to fade out, and i stood there and said something like "ill be back to pick it up, once again, merry christmas!"