I made a list of all the things it never occurred to me to expose him to and I hope it will make socialization easier with my next puppy. The tea kettle is another one. I do think Sundance was socialized pretty well but I always sort of felt the pressure of trying to find ways to get him exposure to things before that ideal window closed. I mean, it's not possible or even necessary to expose them to every sound, because I assume if they're exposed to a lot of different things the whole point is they can handle a lot of different things in the future. But definitely things on wheels, brooms, vacuums, and tea kettles! Although Sundance is fine with the vacuum and broom now, he jumps up on the sofa where he can keep a good eye on it.
That sounds like a pretty adaptive response, actually! LOL!
The other thing is that there are sounds you just can't "manufacture" easily, or, by nature, are sudden and intermittent. (sneezes!) And some dogs just have their quirks about certain noises. Two of mine couldn't care LESS if we sneeze. Pixel comes running from where ever she is and has to CLIMB us and cover our face with kisses to make sure our face didn't explode after a sneeze. And hiccups make her shake. I know MANY other dogs that react this way to moth sneezes and hiccups, but it is FAR from universal. Why? Who knows! LOL!
I'll tell you two things that I will play for Panda's puppies while they are still in the whelping box are thunderstorms and fireworks, starting REALLY quiet, then working up, since I know these are things that bother MANY dogs, and also soundtracks from agility and obedience trials, since they have their own sets of startling noises (especially agility trials with barking hyped-up dogs, banging teeters and paws pounding through corrugated tunnels!)snd I hope at least some of these puppies end up in performance homes.