The smile, it seems, is always there.
It's like Alvin Kamara knows something that the rest of us don't, and even if he decided to share it, we probably wouldn't understand it the same way he understands it.
It's the smile of a man who's unquestionably secure in his skin and in control of his myriad skills. And if that's not smile-worthy for an NFL player, then not much else is.
So Kamara puts in the work before training camp – his balance drills are must-see videos – that helps make him one of the most productive players in the NFL, work that has elevated him to elite status in just 35 games (31 regular season, four playoffs), work that has made him one of the faces of the NFL.
A face that, almost always, appears to be wearing a smile.
"You've got to be (happy)," Kamara said Friday, after the New Orleans Saints completed their seventh training camp practice, when the forecast was expected to top out at 90 degrees, but the heat index pushed into triple digits. "I think – (I'm) blessed, of course – but I think that's just me. I'm just easygoing, fun, trying to make every situation as fun as I can.
"We're going to be out here regardless. I feel like if you're out here with the mind-set of, 'It's hot and we've got to practice and run and hit each other,' it's not going to go good. I try to laugh my way through it. It's done now. I'm about to go in and recover and sit in the AC."
Fitting, because few exude more cool (and calm) than Kamara.
The third-year running back was an All-Pro and NFL Offensive Rookie of the Year as a rookie (1,554 yards from scrimmage on 201 touches, 347 kickoff return yards and 14 touchdowns). Then, arguably, he had a more productive season in 2018: 1,592 yards from scrimmage on 275 touches, 208 combined punt and kickoff return yards and 18 touchdowns to tie the franchise single-season record, including a team single-season record 14 rushing.
Only Rams running back Todd Gurley, with 40 total touchdowns in '18 and '17, tops Kamara's 32 over that period.
Probably, no one tops him in the fun department.
"He's got a pretty low-key personality," quarterback Drew Brees said. "He's a fun-loving guy. There's never really a time where I don't see a smile on his face, where he doesn't look like he's just enjoying being around the guys in the locker room, just little things out here on the field.
"You watch us during what you'd call just a really fundamental quarterback-running back exchange period where we're just working on footwork and timing with run plays and such. And yet after our rep, we'll play catch, we mess around with option pitches and he's smiling, laughing and we're goofing around a little bit, but it's a way to break up the monotony.
"But it also just shows that this is a game and we're going to enjoy it. We're going to have fun. We enjoy being around each other. When it's time to work, it's time to work (and) when it's time to have fun, we can have fun doing it as well."
When the work revolves around red zone efficiency, Kamara seems to be at his best. His nose for the goal line has been unmatched in a two-year period in franchise history. Only receiver Joe Horn (10 touchdowns in '03, 11 in '04), tight end Jimmy Graham (16 in '13, 10 in '14) and running back Mark Ingram (10 in '16, 12 in '17) join Kamara with consecutive seasons of 10 or more touchdowns in Saints history, and his 32 easily tops the list.
"There's a lot of things I can do in the red zone," he said. "From 25, 20 yards in, our playbook kind of gets concentrated and we know what we want to do and we know how we want to attack.
"From being in the backfield, running routes out of the backfield, to even our red zone runs are very effective, being able to split out (as a receiver) and working combos…I look forward to red zone because it's easier to score right there."
The frequent trips to the end zone mean Kamara isn't the only Saint who's smiling.