They always carry cash...
In today’s economy, with Venmo and direct deposit and Square and Dogecoin and whatever new cash-killing cyborg technology is next, carrying actual paper money seems as antiquated and absurd as riding a bike sidesaddle. But in the service industry, cash still reigns supreme.
Cash is easy -- no swiper machine, pen, or WiFi required, no logging each tip in separately, and, most importantly, no taxes taken out up front. In every bar and restaurant I’ve ever worked in, credit card tips were tallied at the end of a shift and included in the nightly totals, meaningless numbers that didn’t translate into cash-in-pocket until I picked up that puny biweekly check that somehow still got decimated by taxes. Cash tips, on the other hand, we’re all mine come closing time, no questions asked. Even if a highly effective tipper drops plastic on the bill, they'll still leave cash on the table. It's the quickest way to a barkeep’s heart... especially if the goal is to become a regular.
... and respect discounts and comps
This is HUGE. Buybacks, free shots, happy-hour discounts -- when it comes time to settle, good tippers remember to count these pretty perks at full price and calculate gratuity accordingly. Just because the bar owner decided domestic pitchers should only cost $3 on Wednesdays doesn’t mean they’re suddenly easier to pull, pour, or wash. And just because that friendly bartender comped your last round of Lemon Drops doesn’t mean his time is suddenly worthless. Tips pay for the labor, not just the product.