Learn English – Meaning and origin of “if you catch the drift”

The phrase "catch you on the flip side" is a very colloquial way of saying "See you tomorrow". It's unusual and unprofessional to see it in a business email.

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).