Did you ever have one of those days? No, ugh. Reporter: That keeps getting worse? Lady, let's go. Reporter: We're at the saddle brook diner in saddle brook, new Jersey. Vince is having such a bad day... See More
Did you ever have one of those days? No, ugh. Reporter: That keeps getting worse? Lady, let's go. Reporter: We're at the saddle brook diner in saddle brook, new Jersey. Vince is having such a bad day he makes everyone's life miserable. Did you lose the formula for hot water? Can I order here or what? I don't have all day! Reporter: By becoming the world's biggest jerk. Is it me? Reporter: When he stomps off -- I'm leaving. Reporter: Traci spots something unieshl. What? Reporter: Something Vince accidentally leaves behind. Wow, I can't believe it. Reporter: A bank envelope stuffed with $100 bills. Now, the question is will people allow Traci to keep the money just because the guy who lost it is a total jerk? What would you do if you saw something like this -- A hot decaf tea! That's a cup with hot water and a tea bag that says decaf on it. All right? I mean, unbelievable. Reporter: As Vince storms out, watch as this man applauds. Can't get water right. Did he leave? Reporter: It seems Vince forgot something. It must be Traci's lucky day. I'm going to keep this. He's a jerk. Don't say anything, okay? Reporter: But the guy who clapped for Vince's exit -- now enters as Vince's protector. The woman found money on the seat there. She did? It was? Yeah, I'm sure he'll be back. Reporter: And moments later, he is. You see an envelope with money in it, anybody, like a bank envelope? It had about $1,000 in it. I'll give you a reward if you have it. Reporter: Nobody's saying anything, huh? They are quiet. Reporter: It seems like everybody's keeping Traci's secret. Thanks for not saying anything. He's a total jerk. Yeah, he deserves it. Yeah, do you guys want $100? Nah, no. Reporter: I'm John Quinones with the show "What would you do?" What did you think of the guy? I thought he was an -- not a nice person. Reporter: Loud and obnoxious. Everything you don't want in a human being. Reporter: He comes back and you didn't tell him anything. He doesn't deserve it. Reporter: He got what he deserves. Yes, exactly. We roll again. What is that? Cup of soup. A cup of soup? Reporter: Keep your eyes on this guy. I'm taking my business somewhere else. You should do anything else than this. Reporter: His reaction to Traci finding the money will change faster than the diner's daily special. He's gone, right? That's not right. Oh, no, no, no. Reporter: At first he wants Traci to give the money back but wait -- $100 to keep silent. That's the deal. Traci goes back to her table, counts the lost loot, then offers even more cash to keep him quiet. Now, he'll take $300, but when Vince returns -- I was sitting right there. Did you guys see an envelope with money? Yeah, she has it right there. Reporter: What? Just like that he turns Traci in. In the black? November. This fella is pointing at you. This gentleman pointed at you. No, I don't have it. Are you sure you saw it because I'm gonna call the cops. I'm not sure. I can't say anything. You said you saw it, but now you didn't. Are you sure or not? I'm not sure what I saw. Someone wants to do the right thing -- Reporter: But Traci wants answers. Why did you rat me out? I told him I knew nothing. Reporter: Does he still want the money? Here. How much do you want? Whatever you think is fair. Reporter: Yes, he does! How much you want? I guess you can keep it all. I'll give you money. Nah, that's all right. Reporter: No, he doesn't! Now we want answers. What's he really thinking? How are you guys doing? Right away, the first thing I said was, uh, "We should find the guy and give him his money back." It would've been the right thing to do. Reporter: But then she asked you "You want some of the money?" And you said yes at first. I did say yes, yeah, you know? Who's gonna say no to free money, you know? What can I say. Reporter: But then you thought about it -- Then I thought about it, yeah. Doing the right thing, you know would've not been taking it which I didn't take it. Reporter: We roll again and this customer takes a different approach. It's borderline ridiculous here. Reporter: He's a ticking time bomb. You don't know how to serve tables. There noise reason to make a public spec Tagle. I'll take my business elsewhere. You don't know how to wait tables. Reporter: When Traci discovers the stack of $100 bills -- He left a pile of cash, right? Yeah. You're going to give him his money back? Yeah. It's the right thing to do. Reporter: He takes action, to return the money. We're going to go get him. And now the bomb goes off. He doesn't even see me or the camera crew. I know you might be having a bad day. Don't ever, ever do that to a young lady again who is trying to work her butt off. Reporter: He's so worked up he still doesn't notice me. Do you that again I'll throw out of the place. Didn't do that, I'm an honest man. I hope you have a great day. Don't ever do it again. Never again. Reporter: Sir, this is part of the show "What would you do?" It's not right to treat people that way. Reporter: Don't keep the money. Don't keep what's not yours? Why should you? Did I earn it? Man works hard every day. It's like $1,000. We start rolling again. They quickly form a posse to force Traci to come clean. She's got it! Who? That one with the black hair. She's got it? Without a doubt. You have my money? I don't know what you're talking about. This gentleman says you have it. They saw it. No doubt. You saw it? Yep. I'm going to call the cops. Reporter: Vince leaves and the customers let loose. Lady, give back the money. I don't know what you're talking about. Are you kidding me? He's getting the police. Just give him the money. It us dnt concern you guys. Why is everybody so upset? It's the right thing to do. Give him that money. It's disgusting. Tell him that you found it. Then I look bad. I don't know what you're talk about. Wow. Wow. She is disgusting. Reporter: Let's do it. Oh, my god. Reporter: You ratted her out right away. Absolutely. She is a thief. She is a thief. Absolutely. Reporter: She offered you a little bit of money. That's stolen money. Reporter: You don't want to touch it? No, no. I'd feel like an accomplice to something. Reporter: But you don't know the guy. Doesn't matter. Not the right thing to do. You got to speak up. I would have ran after her. Absolutely. I would have stopped her. Reporter: What about Vince's lost money? You'll be interested it know it's worthless. He's so good he made it into a $100. Thank you. Spend it wisely. It's "What would you do" dollars with a picture of yours truly on the front. The only found money you can keep today.
This transcript has been automatically generated and may not be 100% accurate.