I have friends who consider bacon to be essential food, mourn the McRib’s offseason, and let their kids nosh on their dried nasal mucus.

But they draw the line at … iceberg lettuce?

“No nutritional value,” they insist.

Iceberg lettuce on a burger is acceptable; as a salad, to neo-nutritionists, not so much.

The line, as we have learned, is not universal. Draw a figurative line in the sand, and it is an indelible boundary that cannot be exceeded. Draw a literal one, and it can be erased with the next high tide.

There are defined lines between fans of the Red Sox and Yankees; Dodgers and Giants; Kanye and common sense.

“Blurred Lines” blurred the line between being an original song and a ripoff of Marvin Gaye’s “Got To Give It Up.” A jury decided a copyright line had been crossed, and ruled in favor of Gaye’s estate.

In sports, the line is clearly defined … sort of, maybe. A baseball or volleyball landing on the line is in play; a football or basketball touching the sideline is out of bounds.

The lines can be arbitrary when it comes to defining greatness. There are Baseball Hall of Fame voters who fill their ballots based on performance and longevity. That explains why pitcher Phil Niekro, who won 318 games in 24 seasons, is in the Hall despite never winning the Cy Young while amassing nearly as many 20-loss seasons (two) as 20-win years (three). Reliever Rollie Fingers, who was inducted in 1992, probably was best known for his handlebar mustache. Fourteen pitchers have more career saves than Fingers, but only four of them are in the Hall of Fame.

Hall of Fame voters draw the line when it comes to the performance-enhancing era, denying such stars as Barry Bonds and Roger Clemens. But then that standard also should have applied to Gaylord Perry for his baseball manipulation, George Brett for his pine tar application and, really, for any pitcher who used a rosin bag.

Baseball draws the line on a career hit leader for betting on the sport. But how much fun would that Super Bowl party be without the prop bets? We draw the line on legalized gambling in Hawaii but refer to Las Vegas as the “Ninth Island”?

It will be interesting to see where the line will be drawn when Kyrie Irving is up for Hall of Fame consideration after he retires.

Hawaii football fans used to have a hard line on loyalty. As a Saint Louis School senior, Micah Matsuzaki was the state’s top receiver. He signed with UH’s chief rival, Brigham Young University. When BYU played at Aloha Stadium in 1989, the Rainbow Warriors fans mercilessly booed Matsuzaki the entire game. The 1990 meeting also was at Aloha Stadium. To prepare for the hostile atmosphere, BYU players booed Matsuzaki during a video session.

Since then, the us-them line has faded. Hawaii football fans had chicken skin during Marcus Mariota’s acceptance speech at the Heisman Trophy ceremony. Mariota, a Saint Louis School graduate who played at Oregon, set up a foundation whose endeavors included buying tickets for youths to attend UH football games. Tua Tagovailoa, McKenzie Milton and DeForest Buckner were among the many who were considered Hawaii’s own while playing for mainland schools.

And that leads to this week’s game between UH and San Jose State. It will be the first time quarterback Chevan Cordeiro will face his former team since leaving the Rainbow Warriors after the 2021 season and transferring to San Jose State.

Cordeiro — unlike Mariota, Tagovailoa, Jayden de Laura and AJ Bianco — was a Saint Louis School quarterback who chose to play for the home team. In 2018 and 2019, he came off the sideline to win games for the Warriors. As a starter in 2020 and 2021, he also served as a co-captain. He worked hard, never complained and mentored teammates.

But after some teammates voiced displeasure over the atmosphere fostered under head coach Todd Graham, Cordeiro decided to enter the transfer portal. His departure set in motion other defections and led to a state Senate hearing that ultimately resulted in Graham’s resignation.

Cordeiro has excelled at San Jose, as expected, and the Warriors are rebuilding enthusiastically under head coach Timmy Chang. Chang, like Cordeiro, was a Saint Louis quarterback who played at UH.

This week, will Hawaii fans view Cordeiro as an opponent who ditched the Warriors or appreciate all that he contributed in the previous four seasons? The line is not clear.