Well, I won't lie, this stamp was inspired by the subject of 'Avatar' fandom comparing all that's blue, has tendrils, flies etc to avatar characters, or simply say they're things that could fit in Avatar world. Avatar was not the first movie with dragons, cat-people, or 6 limbed creatures. Plus apparently many aspects, even the mind binding was ripped off from a 50s sci-fi novel.
To many artists this is NOT a compliment, especially if you have nothing else to say in your comment besides 'oh this looks like...".
There was a case when I was animating at school one of my flying creatures (not even scaly...but with fur) and one person asked me if i was avatar inspired. Everyone knew i wanted to beat the guy with his own spine.
Of course, if I create something and it's similar to something that's already been made, by all means let me know. But other than that, if you feel the need to compare stuff to something, do write a critique, a compliment, or SOMETHING that strikes you personally about the picture before dropping the 'it kinda looks like...' line.
It makes the comment much more bearable.