A.V.
Running across the street to the neighbor to see if Sally can come play or dropping off cookies is one thing. Wanting to come in and visit for a long time is something else. I would prefer a phone call and I call my in-laws before we head over even if it's "Hey, we're not far and could be there in 15 minutes. Is now a good time to come by?" It's not that no one cares, just that people tend to call ahead more and I was taught it was out of politeness. I don't want to come by with one expectation and find out I'm intruding. My DH tells a story about how after he moved out he "dropped by" on his parents and peeked through the mail slot when they didn't answer. He got an eyeful and never again came by unannounced.