I don't believe my comment deserved a downvote. Can you un-downvote it?
Sure, mistakes happen. But only in exceedingly rare circumstances will I undo a downvote. If you would like to issue an appeal, shoot me a private message explaining what I got wrong. I tend to respond to Reddit PMs within several minutes. Do note, however, that over 99.9% of downvote appeals are rejected, and yours is likely no exception.

How can I prevent this from happening in the future?
Accept the downvote and move on. But learn from this mistake: your behavior will not be tolerated on Reddit.com . I will continue to issue downvotes until you improve your conduct. Remember: Reddit is privilege, not a right.

I just downvoted your comment.

FAQ
What does this mean?
The amount of karma (points) on your comment and Reddit account has decreased by one.

Why did you do this?
There are several reasons I may deem a comment to be unworthy of positive or neutral karma. These include, but are not limited to:

Rudeness towards other Redditors,
Spreading incorrect information,
Sarcasm not correctly flagged with a /s.
Am I banned from the Reddit?
No - not yet. But you should refrain from making comments like this in the future. Otherwise I will be forced to issue an additional downvote, which may put your commenting and posting privileges in jeopardy.

Hey it's me, we just played together. I noticed you didn't add me but I sent you a friend request haha, maybe it glitched or something you're pretty cool though like I said before, that's why I got my team to throw for you. It's so cool to see a girl playing in games though. I know you have a boyfriend so I hope he treats you well. Like if I was your boyfriend I'd make you sandwiches while you play and buy you chocolate and give you back rubs and call you cool and laugh with you at all your jokes, not real though because we aren't together (at least yet) ;) Yeah so haha you should totally accept my friend request so we can talk more and have fun together, just as friends of course coz otherwise it would be weird and I don't want to get cooties from you ewwwww (just joking, I would like your cooties) :p\

Hot tip: When someone yells pickpocket start searching for your wallet in the groin area and exclaim 'Thank God my wallet is safely tucked between my testicles'. The pickpocket will see this and assume that the wallet is there. These people usually have very supple and delicate hands so when they try to take your wallet you will instead get a pleasant fondling to your genital area.

Hello when you read this you have 8 days to send this message to 15 people and if you dont
then you will sufur a great videogameitus and if you are a girl shoppingatraumaitusica
which of both will make you tired of playing video games or tired of shopping
if you send this to more than 15 people in less then 8 days you will be very lucky and feel unstoppable (but you really arent so don't jump in front of cars)
if you send it to 15 people in the next 11 seconds you will become a billionaire when you are a teenager and if you sen it in the next minute to 15
people you will get 600,000$ at the age of 14 if your friend who you sent it to sends it to 20 people you will be very good friends with each other and that bond will never be broken EVER so you better get SENDING your computer will selfdestruct if you keep reading this email 10000 times over if you do it 79897897 times the world will blow UUUPPP!!!good luck DevilNinja

Hey guys its Sam hi here with more tips for your everyday life, helping you out, bringing you wisdom. Hey im 27 I’ve been there I’ve done that I’ve been around the block. This next tip has to do with relationships. Love, romance, whatever you wanna call it. I’m gonna give you a surefire way to get her, your special someone, wrapped around your little finger. I mean they’re gonna be just.. Ooohh thinking about you all day. Here’s how you do it. You have to awaken the motherly instinct. You have to get your sweetie, your sweetie pie, to awaken her biological, uh, genetic motherly instinct. and it’s very easy to do. I’m gonna show you how to do it. Kay? You ready? Here we go. (gets on hands and knees) Mommy! Mommy! (smacking lips)Baby Sammy want milk! (slurping) Gimme milky! Mommy! Mooommy! Mommy mommy!! Mom! Mommy! Mommy Sammy want milk! (slurping) Baby Sammy hungry! Baby Samm