We have addressed this in a prior QoD, but it's a fun and very "Vegas" story that's worthy of a re-run for those who missed it the first time around, plus there have been some changes since the original answer ran in 2010, so here it is again, with an update.
The story starts in Chicago in the 1930s, when one Ed Herbst bought a gas station. A marketer at heart, Herbst, who's been called the "P.T. Barnum of Gasoline," soon realized what a cutthroat business he’d entered and that his station had to stand out to be successful. He subsequently used every trick in the book to gain market share. He held giveaways with a fill-up, such as flowers for the ladies and sodas for the kiddies; for the menfolk, he hired teenage girls to pump gas. Everyone got bubblegum. He offered free pony rides behind his station and sold beer, cigarettes, and magazines inside. Ed Herbst is credited with establishing the full-service gas station, as opposed to just the ordinary gas station.
Most importantly, he was admittedly shameless in cutting his gasoline profit margin to the bone and making it up in volume and inside sales. He recognized that car owners would drive two miles out of their way to save a nickel on a gallon of gas, then head inside and pay through the nose for highly marked-up convenience-store goods.
In the late 1940s, Ed Herbst packed up his family and moved west, opening a chain of Herbst service stations as he went, undercutting the competition so severely that he wound up with an unsavory reputation. The story goes that when he applied for a business license in Cheyenne, Wyoming, one of the city counselors, who happened to own a gas station, exclaimed, "If we let that terrible Herbst in, we'll all go under!"
When Ed heard the words "terrible Herbst," he thought that would be a, er, wonderful name for his empire.
The Herbsts settled in southern Nevada, where the big signs above Terrible Herbst service stations tickled newcomers. This writer once came to town with a girlfriend who got such a kick out of the name that she adopted it as a synonym for a hangover. "I had so much to drink last night that this morning, I have a terrible herbst!"
Along the way, the "Herbst" was dropped in favor of just plain "Terrible's," which is symbolized by the familiar "Bad Guy" cowboy logo.
Since this answer first ran in 2010, the family lost control of Herbst Gaming Inc., the separate casino and slot-route facet of the Terrible's empire that filed for bankruptcy in 2011 and is now under the Affinity Gaming banner, but certain casinos, including the off-Strip Terrible's property in Las Vegas, continue to operate under the family name due to a licensing agreement. Meanwhile, Ed Herbst's three grandsons, Ed, Tim, and Troy, have since set up a new slot-route operating company that regained control of that side of things from Affinity and now services over 6,000 machines located in 650 convenience stores, grocery store chains, taverns, and small casinos. In naming the new venture, the brothers kept with the family's eponymous tradition and called it ETT for their initials.
