My pet peeves are:

1. Cel collectors that post about how much they 
love this great cel they just acquired and they 
will never sell it. Then about three weeks later 
they put it on eBay. Then they find another cel 
they rave about and will never sell...and sell it 
within three months. Repeat this process about 
four or five more times and I don't even feel 
like reading their posts anymore.

2. Somewhat similar to #1, but in this case it's 
about what cel series they collect. They rave 
about how much they love  aparticular anime and 
how joyous they are to have gotten such good cels 
from it and then they sell off the cels later 
because they don't want to collect too many 
series. If they only did this once or twice that 
would be fine, but when they do it FOUR or FIVE 
times it just gets me very annoyed. 

With these two kinds of cel collectors, it 
becomes very difficult to take anything they say 
seriously.