Goku is very perceptive of ki. He always struggled with getting a read of someone as a kid, and still somewhat does now, but being able to read ki makes social activity easier for him. He's adapted to it in such a precise way, that he can gauge someone's mood or current state of mind from how exactly their ki is being channeled through their body.
He additionally has picked up on how every person has a unique ki signature, allowing him to recognize someone fairly easy. Goku could be blinded, and would still accurately identify someone he knows with no outside assistance in person. This in turn also causes him to be quite drawn to new ki signatures, especially if they're strong enough to be felt more thoroughly, because the feel of them will be unlike any he's felt before from someone else. Most times he'll have difficulty in describing someone's signature, as the sensations they invoke are usually more abstract in nature. For example, one way he could describe Chi Chi's signature is like "firewood quietly singing as the hearth beats".
Goku does sometimes struggle with sensory overload when he's in a location with dozens of people around, but many Earthlings possessing ki so weak that they're barely detectable, plus he getting into the habit of tuning things out, does help at least.
I don’t care if it’s an overdone idea in the fandom or cliche; I love the headcanon that Saiyans are able to purr. I fancy it being more so like a big cat’s purr - cougars, cheetahs, etc - compared to a domestic cat’s though, and it’s typically an involuntarily action whenever a Saiyan’s feeling very happy and content in a moment (which was a rarity on Planet Vegeta, both because of the Saiyan lifestyle and because purring was mostly perceived as showing “weakness”).
But imagine Vegito and/or Gogeta purring with you 🥺 They’re naturally so guarded and not ones for displaying much “sentimental” emotion, but you make them feel so loved that they can’t help it. It eventually becomes a normal sound for you to hear, especially during cuddle times. They press their faces into your neck or the crook of your shoulder and the soft rumbling from their throats is quite soothing (and ofc endearing) to you.