On New Year’s Day, my 18-year-old granddaughter learned something unbelievable about her father, a matter so astonishing that she was both shocked and impressed.

Years ago, my son-in-law turned down a call to serve a mission in Costa Rica for The Church of Jesus Christ of Latter-day Saints.

He decided at the last minute it just wasn’t for him, that he was going for everyone else but himself. He’d much rather stay home and marry my daughter. And I’m glad he did.

Granddaughter • “Really! Why haven’t I heard about this before?”

Him • [Shrugged] “Wasn’t a big deal by the time you came along.”

It was a big deal at the time. I was there. He endured a lot of family and social pressure to serve the Lord by doing something that had every possibility of being disastrous for himself.

My granddaughter — who isn’t a Latter-day Saint — understands. In the past couple of months, six of her friends have returned home early from missions. One because of an injury, but the rest because they discovered that the mission environment simply wasn’t for them.

It certainly wasn’t for me, but I went anyway. I don’t know what it’s like today, but 50 years ago, mission life in South America was stifling.

We had almost no contact with home. We talked to our moms by phone on Mother’s Day — if the lines were working. And we got mail once a week.

But no missionaries left unless they were sent home in disgrace for misbehavior. Dedication was a huge factor in staying out, but so was the reality of enduring shame if we went home early.

I was already familiar with shame. When word got out that I intended to go on a mission, supposed friends tried to shame me out of it, trivializing what I knew was going to be difficult. Only one of them bothered to look me up when I got home, and I don’t miss the rest.

Despite the genuine feelings of going insane at the time, I did the entire two years. But there were some who wished I had given up and gone home.

They expected I would be sent home after I told the mission president’s first counselor to consume something vile (and using the precise vile word to describe it) one morning when he tried belittling me in front of a bunch of other elders. But I was young and immature then. Do I regret my behavior today?

Nope.

Better missionaries than Elder Kirby were sent home. Out of 250 to 300 elders and sisters, I think we lost four during my two years. Oddly, it wasn’t the two who got shot, the one who was stabbed, the four who had a parent or sibling die, and the 40 or 50 who received “Dear John/Joan” letters.

Is shame a factor in young men and women deciding to stick with a mission? Yeah. Shame is probably one of the strongest emotions humans have next to love. It’s our go-to method for people who don’t measure up to our arbitrary standards.

Though the church has developed programs to help early returnees and the culture is becoming more welcoming, some stigma, unfair as it is, still exists. Missionaries know that their congregation and family may speculate about their worthiness and/or commitment to the gospel. Like it’s any of their business. But it’s the price of being true to yourself.

I stuck it out. But I wouldn’t be able to do it today. I’m older now and even less cooperative than I was back then. But it taught me a valuable lesson.

Given what I went through, I understand when young missionaries come home early. After all, if God called them to go, couldn’t he also call them to go home?

Robert Kirby is The Salt Lake Tribune’s humor columnist. Follow Kirby on Facebook.