How do I avoid becoming a crotchety old man? I’m seriously asking.

You know the type, probably a good father or worker, but serious faced all the time, never smiles, often in a bad mood, very cynical. It’s just I feel like I’m on the path to this, I’m 28, just escaped 12 years of food service so I’m already super cynical and if someone comes up to me, I’m super ready to shut down whatever’s about to happen. I feel like working with customers for years I’ve learned to have giant walls up and I can’t seem to remove them. I see the other guys in the factory I’m working at laughing and joking all the time, I think of myself as funny but it’s always deadpan humor and I wish I could genuinely smile and laugh and make friends with the other guys. Any old timers or well travelers out there have any advice?