What's a dead giveaway that someone is a bad person?

When they do not return the grocery cart to the cart corral.

I'd say it's conditional. At a certain point, it's on the business themselves. For example, a giant parking lot with one or two cart returns only, in a front corner.

A massive sprawling Walmart parking lot with only one return, and I had to park really far away, and it's super busy and trying to get the cart to the return requires going through multiple rows? I'm a goodie two shoes who will clean up after others, and tries to improve places... but I've got limits with time, effort, and desire to deal with crowds of people in parking lots.

If they have good placement though, then yes, it's absolutely on the individual.
- Unless you have a medical reason for not being able to walk to the front to return it, you're still an asshole if you don't.
- This is the kind of balanced, nuanced take that will get you absolutely murderlated with downvotes.
I doubt you can judge someone as bad based off that

EDIT: I'm gonna go with better terms here: Not responsible enough and ignorant, I still don't believe someone can be considered bad as a person for this.
- There are two main reasons you wouldn't return carts to a cart return location:
  
  Fuck them people
  
  My time is worth more than this
  
  At the very least the person is inconsiderate, and worst a complete psychopath. Both are not great signs, and all the ones between are also not positive aspects.
  
  You'd think something that small wouldn't be much of an indication on a person's overall nature, but it's nearly always the little things that add up to the whole thing.
- OP doesn’t put his cart back! Shame!
- There's two possible scenarios
  
  you think your time is more valuable than others, thus making you an asshole
  
  you simply don't give a fuck about inconveniencing others, again making you an asshole
- It's actually a great indicator as to their view of the social contract and obligations to others.
- Someone sounds like they are projecting...
- Cart Narcs demonstrates that you can lol
- I find the people who judge others based on cart return status are the real assholes.
- I mean.. you asked people for red flags that someone is a bad person, not 'what actions make someone a bad person'.
  
  I think they're right and Cart Narc did all the field research for us.
  
  Check it out
This is such a strange phenomenon to me. In all the countries I've lived in, all but a few select stores have a dongle on each cart that takes a coin to unlock it from the chain of other carts. It's perhaps the cost of a back of toilet paper, but that seems to be sufficient for it to be exceedingly rare to see an abandoned cart. One can only imagine that any such carts are quick prey for enterprising teens looking for a quick boost to their candy fund.
Oh man. I live not too far from a Walmart (about 3 miles by car, but 1 by foot with shortcuts). Recently, someone in my neighborhood has started walking to Walmart, filling their cart, then just bringing the cart home with them and abandoning it on the access road in our neighborhood. We are 6 carts deep and my anger towards the perpetrator grows every day.

"You can easily judge a person's character by how they treats those who can do nothing for them."

... or something really close to that. I'm too lazy to look up the actual quote right now.

Mean to animals

Reminder that eating animals is unnecessary and cruel
- don't worry, people don't eat penguins except in extreme circumstances. even if you were a penguin, you'd be pretty much safe.

If they're mean to waiters, cashiers, janitors, etc.

Additionally, whether they think someone has money, influential friends, etc determines whether or not they treat a person well.

Being unable to admit they are wrong or don't know something. I feel like it's one of those traits that snowballs into someone coming off as obnoxious and elitist

God, reading all these comments while baked in a hammock was a trip. I highly recommend the cart saga.

Everyone can be a friend when it's easy and convenient. It's during the bad times, when they suffer and it's not so easy to keep cool, that their true values or lack of come to light.

Haha yup, that's when the true color comes out!

Animals don't like them.

My special needs kid is terrified of pets. And they react in kind -- animals that are sweet toward a smiling, calm person will lose it in his presence.

Is anybody "bad" here? This seems like the worst kind of judgment based on initial appearances, rather than understanding.
Haha this can be a good one, especially dogs, they are great at sensing people. But they are living things too, and they can be wrong as well. Also sometimes we could misunderstand them, maybe it's not that they don't like someone, maybe they are hesitant towards new people because of a bad history with humans until the dog met it's current owner. A lot could be applied.
- Absolutely. I was thinking of my own experiences where I saw animals I knew react very negatively meeting someone I didn't. In one instance, the guy later turned out to be abusive, in another, dude was a rapist.
  
  But it certainly isn't a universal truth.
Hitler is a good guy then?
- LOL

I'd say it's when they get angry when you tell them the impact their behavior is having on you, instead of actually trying to have a discussion and sort the problem out.

Or they get angry with you for enforcing your boundries.

Or they gaslight you about your boundaries..
- My personal favorite is when they gaslight you about whose “fault” it was. Failing to recognize that boundaries were only enforced because of decisions they made.

Not to bring Trump into everything, but yeah... Trump supporters. Bonus level of shittiness if they have a maga hat.

Literal blood on their hands, bodies falling out of their ceilings and closets, and/or being a billionaire.

Folks who opt not to clean up after their dogs. Particularly in public areas.

I can't stand this. Nobody wants dog shit on their lawn. If I can pick up big piles of shit from my dog you can too.

"I call them how I see them."

"I'm just brutally honest."

"I'm just telling it like it is."

These phrases are used exclusively by rude, obnoxious, condescending assholes trying to justify being shitty to other people for no reason.

They don't like animals.

What kind of animals? I'm not crazy about badgers.
- good god, and you feel like you can just admit that for everyone to see?
  
  classic example of Internet anonymity making people feel they no longer need to follow social norms.
- I'll allow an exception or two, as long as it's not dogs (unless the person has had a negative interaction with dogs).
  
  Edit: Badgers are adorable and I can't imagine what kind of nuisance they are as someone who lives in the US. Maybe like a groundhog? They're kind of cute but so destructive.

"I like people/politicians who tell it is like it is!"

This always means expressing popular grievance with a particular style that scapegoats everyone else for a group's problems.

When their opinions are... very extreme.

Earlier today, someone told me that they'd wish someone were no longer living if they mentioned liking a certain type of pizza. It definitely wasn't said in a joking tone either (not that I'd really want to be around someone who made that type of "joke" in the first place) - that was a pretty obvious indicator that they were a bad person in my book.

It was done under the guise of "I don't like to sugarcoat things" 🙄

An unwillingness to admit fault, and/or learn from one's mistakes. It's the biggest and reddest of red flags.

Extreme racism.

How they treat their waitress at a restaurant. Big red flag.

People who constantly ask for favors.