What would you do if someone acts this way?

He's a loner, so leave him alone. Not all of us are social butterflies, and I'm am more like this person you describe. I don't go to work to socialize or make friends, I go to work to get the job done. I also don't make friends because I might be your boss one day and have to fire you, so there should be nothing personal about that decision.

Nothing and leave them be? Obviously they’re not big on sociality and prefer to keep to themselves. Nothing wrong with that. I’m more or less the same way. He’s shown he can be decent and friendly whenever he does interact with others, so it’s not like it’s hurting anyone. Why would anyone need to do anything?

I'd do nothing, he's probably an introvert like myself and I would let him be.

Sounds like an introvert ,and why so many feel they must do something other then accept him is beyond me.fir introverts people suck the wind out of their sails,they loose their energy while extraverts get their energy from yapping with others introverts gain theirs when alone. Nothing wrong with either it just the way it is and we need to understand and accept it that's all. When and if he wants things any different he will just dont count on it.he is probably very content. Now there is a wide range from being either an introvert or an extravert so let people be who they are .

He seems civil and convivial.
No need to push him and make his life your life.
Leave him be and all will be well.

Sounds just like me. Not everyone is a people person and you shouldn't try to change them.

I leave him alone because I act that way.

Respect his personal boundaries and MYOB.

I’m this guy, what’s your problem?

Let him be. He's not hurting anyone.

...he eats breakfast at work?

Leave him alone.

i would do this thing called mind ur own business 🙂

Some people like their own company

he just wants to be alone

Let him do his own thing.

He’s shy?

Maybe he is a lone wolf. Nothing wrong with it.