I was creeped out once when I was waiting in line for my car emissions test. The Yellow Pages app popped a notification: “Will your vehicle pass the emissions test? Make an appointment with a certified auto technician today.”
A friend coming home from work saw the neighbor on a new riding lawn mower. They chatted for awhile and the friend commenting that he was thinking of getting one.
They finished chatting and he went inside. Pulled his phone out of his pocket to check his emails. It already had an ad for riding lawn mowers (and he continued to get them). The idea of a new mower had just occurred to him while talking with the neighbor. He figures the phone is listening in all the time.