Anime fans supply a ranking of the moments they realised their DNA had become corrupted into that of a creepy anime otaku.
The ranking, which is clearly using “otaku” in the sense of “anime otaku”:
1. When you fell in love with an anime character
2. When your PVR’s hard disk filled up with anime
3. When you noticed yourself reading a character’s lines in a novel in the voice of their seiyuu
4. When you started staying up until early in the morning to watch late night anime in real time
5. When you started saying the lines of anime characters in actual conversation
The newest addition to the list would likely be “when you read the above list and realised all of them applied to you.”
See also a ranking of what signals corrupt otaku DNA provided by non-otaku observers.