Of course you have the right to express your 
opinion. However, the considerate thing to do, 
if you are a mature, responsible adult, is to 
express your opinions in a respectful, informed 
manner. Respectful meaning, don't put down 
others opinions and treat them as though they 
are idiots.

Your first response was, to be perfectly honest, 
very ignorant. Obviously you don't know much 
about DBZ, since you dislike it and thus have 
probably not watched the whole thing. So of 
course you wouldn't know that the cels up for 
sale are very sought after and from memorable 
scenes, and as such are worth every penny. 
However, insulting the seller is a very rude 
thing to do. She's already taking a loss on 
those cels, and now you have to come along and 
call them too expensive? Although you have the 
right to express your opinion, if you don't know 
what you're talking about it's better to keep 
your mouth shut. "Better to keep your mouth shut 
and be thought a fool, then to open it and 
remove all doubt." Those are some wise words 
that you should listen to. Your original opinion 
was completely uninformed and thus very 
insulting, because you had no idea what you were 
talking about. That's why people turned against 
you; because your opinion was not only ignorant, 
but also very rude and insulting towards the 
original poster as well. Go reread your first 
post. Is that really the best way you could have 
put things?

And as for being on-topic. This is a message 
board about anime and cels. Thus, your post was 
not off-topic to that. It was, however, off-
topic to this particular thread. It is a FOR 
SALE thread. Goldknight did not ask for opinions 
on these cels; she was merely advertising the 
fact that she was selling them, which is her 
right. If you had kept your response to "I think 
that the price on your cels may be a little bit 
high, but I don't like DBZ so I'm not aware of 
the current market surrounding those cels", 
there wouldn't have been a problem. However, 
flaunting your ignorance and dissing the show 
(and, by association, everyone who actually has 
the gall to LIKE such a show) was inappropriate 
to the thread. If you want to bash DBZ, start a 
new thread entitled "I Hate DBZ" or something 
similar. I mean, honestly, can't you see how 
this type of behavior is just begging for a 
flame war?

This isn't about whether or not you have the 
right to state your opinion. You have that 
right, just as I have the right to like whatever 
show I like (including DBZ, although I'm not a 
14 year old boy), and Goldknight has the right 
to sell her cels for whatever amount she wants. 
After all, a cel is only worth what someone is 
willing to pay. As for this particular 
situation, it's about simple etiquette. Someone 
is offering cels from a show you dislike for 
what seems like insane prices. Roll your eyes 
and move on, or bitch about it to your friends. 
Don't just hijack the thread with an uninformed, 
blatantly ignorant opinion.