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.

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.