First of all, I have hated the phrase 'pet peeves' ever since elementary school, but it has its place.

I had an idea that if I were to do a blog series, it would examine common fantasy/sci-fi tropes and whether they make sense in terms of history. Of course, fantasy doesn't have to be just like history--that would be historical fiction--but in order to build a realistic world you have to have a certain level of realism. Maybe it sounds odd to talk of realism in fantasy, but I think even fantasy has to have rules. (Even Terry Pratchett has a few rules...I think.)

Anyway, I'm not going to do that blog now, but I might just list a few 'pet peeves'. These are the sorts of anachronisms that make me shudder when I see them and probably turn me off reading more of that book/series:
-wearing armour all the time
-thieves guilds
-taverns with wenches and frothy mugs of ale
-secret passages
-kids having 20th C lives, with free time and school, etc
-armies organised in modern fashion
-complete lack of actual feudalism
-weapons cleaving armour like paper
-(American) frontier style countryside with log cabins and hearty (free) folk
-many more!

Yes, I suppose I'm quite picky, and no, fantasy does not have to slavishly replicate medieval Europe. However, most fantasy tends to borrow tropes from across centuries of human history without acknowledging the inconsistencies that brings. Fantasy worlds tend to be very static, from a cultural/technical evolution perspective, with all these bits and pieces of history mashed together and not much thought into how things got that way.

For example, even Joe Abercrombie's The First Law Trilogy (while obviously brilliant) has viking-like barbarians across a narrow stretch of water from 16-17th C. mid-Europe. It just seemed odd to me, but on the other hand throwing these things together is what makes fantasy so much fun.

Still, I think the best world-builders make sure their new worlds have a proper back story governed by some realistic rules--even if there are elves.