This has happened a few times: I’m walking outside down a moderately busy residential-ish street. My phone rings. I don’t hear the ringer at all, and it takes me several rings to notice the vibration because my phone is in my purse. The not-really-that-loud sounds of traffic completely obscured the sound of the ringer.
The sound of running water is also very other-sounds-obscuring, especially when the running water is right next to me and the other sounds are further away. If I’m in the kitchen or the bathroom using the sink, I can usually just barely hear someone speaking at normal volume in the rest of the house, but I can’t understand what they’re saying.