NAHANT – It celebrated its 20th anniversary this holiday weekend, but people still get its name wrong.”I’d say 99 percent of people still call it Captain’s,” said Seaside Pizza owner George Mastoras, laughing. “We answer the phones ?Seaside’ but I hear it out there as Captain’s ? (the change) it’s just not happened.”Mastoras explained that the business was originally called Captain’s Seaside to distinguish the location across from Short Beach from the flagship business Captain Pizza in Swampscott. Mastoras said he changed the Nahant Road location’s name to Seaside Pizza when he sold the Swampscott location three years later.But Nahanters seem resistant to change, he joked. That may be appropriate, however, as Mastoras noted that few things have changed since the business opened in 1991. The restaurant’s size and its arrangement of tables and chairs remains the same, Mastoras said, and the menu remains consistent.”We stick pretty much with the business as is and it works well,” Mastoras said. “Good product, fair price and fast service so that people can get back to tanning or whatever they do on the beach.””When the weather’s good, we’re crazy,” added employee Rose Manning. She reported that there was a line out the restaurant’s door for most of the holiday weekend.But, even after 20 years, Mastoras said he still is surprised that he ended up owning a sub shop in Nahant.The Greek immigrant who grew up in Peabody said he initially studied pre-med at Boston University, planning to be a pediatrician. But he explained that he soon realized that he enjoyed the part-time job at Mino’s Roast Beef in Marblehead that he had held since high school to the medical-student world. He switched to studying business and economics and returned to Mino’s after graduation, he said. In his mid-20s, he said he purchased Captain Pizza and then opened Captain’s Seaside at age 28 – thinking it would be a seasonal business. But after the first summer in 1991, he said that nobody – neither the customers or the employees – wanted to pack up. He said he has been open year-round from 7 a.m. to 10 p.m. since and purchased the variety store down the street about 16 years ago.”I think we’ve got a good formula,” Mastoras said. “When you have something, why change it if it works?”And part of what he attributes to making the business work are the community’s kids.”You can see kids, 7 or 8 years old who come in on their bikes,” he explained. “I feel good that I can have the parents’ confidence that their kids can come here.”He also estimated that he had employed about 70 or 80 local youths over the years.He greets every customer by his or her first name and estimated that he had hired 70 or 80 local kids over the years to deliver pizza.”It’s been more than good,” Mastoras said of the last 20 years. “It’s the atmosphere, it’s the community. I can go and make money anywhere, but it’s not just having a sub shop, it’s having a sub shop in Nahant.”As for the next 20 years, Mastoras said he has plenty to keep him busy, including the variety store and a car dealership he owns. But as he gets older and slows down, he joked that he might be able to see the rest of Nahant.”Maybe I’ll be able to visit the beach across the street,” he said.