If your in a position of authority and you make a decision there will always be people who will disagree and kick up a huge fuss over it...there is a thread in News and Questions that has just been locked which gives a good example...
I wouldn't take it personally, however, if you think maybe what the user said had some truth, try and be a little more moderate in your moderation...but you can't go to the extreme of letting it askew your judgment.
Or...you could just "unscrew their head and shit down their neck"