This Redditor's mom is a teacher who said there's a connection between the kids with bad parents and kids with dirty fingernails and unbrushed teeth.

Unfortunately, those kids grow up to become adults who don't know how to wash their hands properly or regularly brush their teeth.

"Nothing is ever their fault. Either their parents refused to admit their child was not perfect or they think the world is out to get them." -u/pajamakitten Either way, we're stuck dealing with it.

It doesn't take much to throw something out, but too many people don't do this.

They were taught to treat the world like trash, like the Redditor's ex who would toss trash out the window while driving.

"It’s a good test because it isn’t technically illegal to do so, just inconsiderate and so you get a real test of how people behave when they don’t have to follow the rules." - u/Punchable_Hair

"I'm so [expletive] tired of having to scrape gum off the bottom of my shoes cause someone couldn't wait til they got to a trash can. & it's even worse when the gum is spit out only a few feet away from the can anyways." - u/iamnumber47

No one wants to eat beside someone who is smacking their mouth while eating or talking with food still in their mouth. This is gross, extremely rude, and preventable by parents.

"The way they argue. If it's an endless shouting match with no chance for the opposing party to so much as speak, it's a good sign they were either spoiled or abused." - u/theseapug

"Had a manager who always thought I was angry at her when I addressed her on a walkie, and would respond as if I was being hostile. No, that's just the way I sound." - u/DreadedLee

It's basic respect — you finish something, you put it away.

Anyone who just plops down on the couch instead of taking care of their own mess wasn't taught consideration of others.

"People who play their music super loud on a quiet train/plane/bus. Nobody wants to hear your [expletive] playlist dude, wear some headphones." - u/ado_adonis. Good parents would've taken their kids headphones away when they were young.

"I don’t care how you say it (cheers, thanks, etc) but I just think it’s common decency and says a lot about a person if they don’t." - u/ellofthewisp

An attentive parent would feed their kids when they were hungry; bathe them when they were dirty.

Those who were neglected in this way grow up to neglect themselves.

"Running reds, cutting people off, weaving through traffic and road rage are all signs you grew down not up." - u/osublackout21. To add to this list: tail-gating and driving extremely below the speed limit.

"When I see the clothes, sneakers, handbags, etc. so many kids pile into their own cars, it's clear none of them are working for their money. When they're finally on their own, expecting to make 60 grand a year starters with a high school or bachelor's degree, it must be a rude awakening." - u/carmium

This Redditor's boyfriend uses forks and spoons like shovels, which means he uses a fist to hold utensils. He'll also avoid large cuts of meat since he can't use a knife very well.

"People who can not say ''I love you'' or basically express their love. I have met people who do not even know how to hug someone. These people can not show their love because they have not seen love." - u/ICantFindNicknameXD

"Or, more importantly, not realizing that they cannot keep their animal(s) properly. Being unwilling to admit that they aren't giving the animal(s) the care they need to be healthy and happy. Refusing to rehome their pet(s)." - u/IiASHLEYiI

Some might call this being a Karen! According to this Redditor, they may make a scene in public and can't "debate" with someone unless it's them steamrolling the conversation.

"Everyone hates losing, but some grown people act like you betrayed their entire trust when you beat them at a game. It just gives me a feeling of 'Oh wow, your parents let you just win everything when you were a child.'" - u/Kathihtak