Differences of Opinion

Yeesh, I seem to be having one of those days--or evenings, depending on your perspective. I have not set out to deliberately cross swords with, or offend anyone today, but so far I can count three distinct incidences where it seems I have done so.

Might be best if I just shut my mouth and write for the remaining few hours and avoid anymore flying bullets or snapping teeth that clash together an inch away from the end of my nose. O_O

Actually, one of the incidences was more of a debate than a disagreement, and I thought I would share it here.

One of my author pals and I had a lively debate earlier this evening on the subject of reviewing books.

My friend is of the opinion that writers ought not to review other writer's works and I think that it is fine for any reader (writer or otherwise) to offer their opinion of a book, that's what a review is, basically and whilst I don't call myself a 'professional' reviewer, I don't see anything wrong with reviewing or giving an opinion about another writer's work

I don't think that anything I say could really influence sales of a book, but my friend thinks that it is unfair for a writer--unless they have won the nobel prize for literature, to criticise a work and possibly cause a decrease in sales with their opinion.

Q4U: What do you think? Can anyone review a book, or should it be left to 'professional, qualified' reviewers?