Shatner became an actor at 6, he said, when he realized he could “make people laugh and cry.” He grinned. “Sometimes they laughed when I played drama and cried when I played comedy.” Then, stentorian again, he intoned: “I. Have. Striven. For. Genius. All. My. Life. But I have known failure.” Shatner was interviewed once by a snarky British talk-show host, who showed scenes from Shatner’s TV cop show, “T. J. Hooker,” and asked, “What do you think about your acting?” Shatner replied: “Oh, I was terrible. How could I have played it that way?” Outside Starbucks, Shatner said to me: “If someone criticizes my acting, they may be right. Sometimes you shouldn’t work so hard” to entertain. Then, softly, he said: “I never thought of myself as a great actor, like Olivier. I was a working actor. I entertained people and always tried to be terrific at whatever it was.” His problem and his salvation. He played so many different roles that “people couldn’t define me like they could De Niro. I took whatever work came my way to pay the bills, even if it wasn’t a decent role.” His motto was “Work equals work,” which destroyed any hope he had of being taken seriously as an actor but also brought him longevity, wealth and fame. “I was always grubbing,” he said. “But I was saying the words somewhere.” He leaned toward me and said, with mock import, “I love to evoke the bones and meat and thoughts of characters.” He put his hand on my knee, squeezed gently, then said with breathless intimacy: “I said this one line for Priceline 20 times. I struggled to get the nuance. My silence reverberated in the ether.” His face was close to mine, as if imparting a great secret. “If you add a car and a hotel room, you will get an even better price from Priceline.com.” I nodded. “See! You got it!” Then, matter-of-factly, he straightened up and emphasized how much satisfaction that one line gave him. “A pro takes the job knowing it’s not a great role, just a paying job. But every word has music in it. My satisfaction is trying to reach that music.”

I asked if he regrets anything about his career. “Regret is the worst human emotion,” he said. “If you took another road, you might have fallen off a cliff. I’m content.”

What makes him content, besides the money, is the adulation he gets from his fans. People thank him for the years. Six-year-olds, 20-something bloggers, old ladies. “Bloggers think I’m cool,” he said. “I wish I knew what it was about me that was cool so I can repeat it. I’ve been in front of people their entire life. Oh, there are so many iterations of William Shatner.”

It was the Internet generation that pushed his fame to its current height. Shatner said with wonder: “I learned the name was Priceline.com. You mean dot-com is a thing? Someone licensed dot-com? They’re making money off it? That was my education to the Internet.” So he hired someone recently out of college to teach him the mysteries of the Web. Priceline paved the way to Denny Crane, when David E. Kelley, the creator of “The Practice” and “Boston Legal,” saw the commercial, and that role then led to “$#*! My Dad Says,” about which Shatner had doubts. “Sitcoms have problems,” he said. “How do I play through the laugh track?” When we met, he also didn’t have a handle on the father yet. “He seems to be a codger, but he isn’t,” he told me. “He’s irascible, but is it an act?” When CBS was filming the pilot, the real Sam Halpern stood up and called out: “That’s not right. I drink bourbon.” Justin Halpern told me that when the two men met “they said hello, took a picture, then parted ways.”

Liz returned with our espressos and oatmeal. Shatner complained about his oatmeal and ordered me not to eat mine. I told him it was fine. He said: “Do. Not. Eat. It.” Liz gasped and said, “No, no, no!” She grabbed Shatner’s espresso out of his hand. “That’s the one with caffeine.” She glanced at me and said, “The one thing Bill doesn’t need is caffeine.”

Ten minutes later, I was weaving in and out of traffic, passing 18-wheelers in the rain, trying to keep up with Shatner. I pulled up alongside his S.U.V., lowered my window and was drenched with rain. “I need gas!” We found a gas station. While my car was being fueled, I noticed Liz was gone from his truck. Shatner grinned. “She was a pain,” he said. “So I let her out by the side of the road.” Liz emerged from the restroom.