Some stories:
Walked into a friends house one day and he was keeping his granddaughters cat. Cat freaked as I walked in , bounce off the wall and landed right on top of the speaker, flopped onto the end table and broke a figurine.
I bought a Salamander cabinet off craigslist. When I entered the house some funky food odor was pungent. Put cabinet in car and soon realized the cabinet stunk as well. I disassembled it and scrubbed it repeatedly with baking soda. It still took months for that odor to subside. Never did put a finger on what the hell that was.
I kept my neighbors old Lab one day. He just lumber around most of the time. But ever now and then he would get a burst of energy and start slinging his rope toy around and for some reason insisted on doing it right on front of my floor standers. I kept redirecting him to other rooms but he would just run back right in front of my speakers. WTF?
I always perk up when I see smoke,pet and kid free.