The reason we find red and yellow so well tied in together is because we see it so often to the point our brain comprehends it looks pleasing.
Sour peach rings? Red and yellow.
A handful of DC logos? Red and yellow.
Certian characters from a show/movie you like? They can also be Red and yellow, sometimes both colors at once.

Yes

Blood and CO(NH2)2

Ok but if we were in an alternate universe where it was blue and purple instead of red and yellow then red and yellow would look fuсking stupid

Haters will say this is a coincidence

does sammy date a yellow bear tho

I mean, in the first few seasons of the show they DEFINITELY had something going on