Weeaboos will usually-
1- Combine japenease words in their native language, to demnostrate their awesome 5 word vocabulary (AKA "OMG LIEK DAT IS SOOOO KAWAII!")
2- Spout anime related refrences when the situation REALLY doesn't call for it, thus making you facepalm
3- Will blab about how awesome japan is and will fill you with "accurate" information based on what they saw in highschools in various animes.
4- the really DERP weeaboos will also do and say stupid stuff like claiming they managed to get a better control of their chakra flow (this one is a real example, from last year, my last year in highschool. i actually punched the fucking faggot on the spot)
these, among various other reasons.
people like that give everyone the imperssion that if you watch anime, you are a retard.