Do NOT mess with Demi Lovato -- especially if you're a member of the pesky paparazzi. The 21-year-old "Really Don't Care" singer took to her Twitter account on Monday night to address a photo where she was clearly giving the middle finger. Demi carefully tweeted, "When are paparazzi gonna learn? If you're respectful to me, I'll be respectful back. Why does it have to be a war of celebs against paps?" and then "Of course if you yell horrible things, I'm not gonna work with you. I'll pose if you are respectful and not being bullies." I mean she does bring up a good point about respect = respect but did make the accusation of calling them bullies. This all went down last night in NYC where Demi made an appearance at the Logo Trailblazer event—looking amazing BTW. It was in NYC that a paparazzo took a pretty low blow by telling her to quote, "Keep her nose clean," a clear reference to her struggles with drugs in the past. That's when Demi flipped the bird -- we don't blame her! She also tweeted to her fans, "I wanted to stop for my fans today/tonight really bad because I love you so much but I can't deal with how mean those paps are... I always try to stop because I appreciate every single one of you, so if I don't get to you please know I'm sorry and I love you. Sometimes staying strong means not putting yourself in uncomfortable or triggering situations." Do you think Demi did the write thing here? And click this snazzy video box for 11 guys Demi has dated, cause you can never have too much Demi in your life! I'm Misty Kingma, proud Lovatic and I'll see you soon here on the Internet! I mean, ClevverNews.