Learn English – Saying for “don’t talk about things you don’t understand”

You catch more flies with honey than vinegar or, sometimes you catch more flies with honey is an English proverb. It doesn't have a counter-intuitive meaning--if you are trying to catch flies, you are literally going to attract more with honey. That is, you're going to get what you want (in the proverb flies, but in life any goal) with sweetness rather than acidity.

This answer explains it similarly:

Flies represents anything you want to achieve. Honey (sweet) represents anything pleasant that you do to get what you want. Vinegar (sour) represents anything unpleasant that you do to get what you want. It tells you to use nice methods rather than unkind methods in dealing with other people.

This is a saying that means: you will be more successful in life being sweeter, or nice rather than being, mean to people, not nice and doing hurtful, dishonest things in life.

This forum makes some guesses at its origins, noting:

The proverb has been traced back to G. Torriano's 'Common Place of Italian Proverbs' . It first appeared in the United States in Benjamin Franklin's 'Poor Richard's Almanac' in 1744, and is found in varying forms..." From "Random House Dictionary of Popular Proverbs and Sayings" by Gregory Y. Titelman (Random House, New York, 1996).

The generic term collocation includes idiomatically paired nouns, which both OP's examples are. So I'd say they are collocated pairs.

Other idiomatic usages such as strong tea and powerful computers are also collocations. In those cases, competent speakers recognise powerful tea and strong computers as "wrong", primarily because we're used to the other versions. Grammar and meaning aren't really relevant - it's just a matter of what people happen to say.

It's also worth noting that we never say it's raining dogs and cats. But as this NGram shows, we actually use that sequence more often than cats and dogs when we're not talking about the weather. Word sequence is one of the attributes of a collocation, though - coach and horses only occurs in that order.