Two stick in my mind:
One guy was a maitntence worker at an apartment complex. He used to be a sniper in Vietnam. Boy did he have some fancinating but ugly stories. He also had some conspiracy stories about his brother who special ops. Stories about secretly assisting DEA down in central & south America were they would climb aboard drug trafficer's boats, kill everyone, take $650,000 of the $750,000 and report it as $100,000 seisure. Etc.. Don't know how much of what he had to say was true, but it made for good stories.
Then the other guy was a WWII vet. Landed on Normandy within the first few hours. Was wounded, nearly blown in half at the lower torso. Lifted his shirt to show me the scar. I have never seen a scar like his, and quite honestly don't know how he survived, especially back then. He was lonely and enjoyed having someone to talk to, but I left feeling a better man for having met him.