What makes an epic fantasy novel fantastic?

This blog is dedicated to my favourite genre - epic fantasy. I have always loved reading epic fantasy, and am constantly on the look out for new authors and novels to immerse myself in. If I think of my favourite epic fantasy books, there consistent elements that jump out at me; elements that have made these novels winners. Here are three things that (in my opinion) that make a good epic fantasy tale linger in the reader's mind, long after they've turned the final page:

• a richly drawn, believable world. From Middle Earth to Westeros, epic fantasy needs a world that readers feel could actually exist. I like worlds with a detailed, unique history, distinct flora and fauna and a realistic depiction of geography. A really good epic fantasy world take the role of another protagonist in the story; and as such should help shape and drive the plot, as events and characters do
• a rich cast of characters (just not too many) with a main character (or characters) that I can really identify with. No superheroes please. If our main character has lost his family, his job, and witnessed the destruction of the world - I want to see a real, human reaction to such events. I've read so many 'coming of age' stories that I tend to avoid them these days; instead I look for tales with characters who go through life-changing events that shape and alter them and their perception of the world forever. I like stories with flawed, gritty characters. Writers who stay with my favourite character's point of view for large chunks of the book please me, as I enjoy feeling as if I'm looking over this character's shoulder and living the adventure with them
• a unique, intriguing plot that may, or may not, include a quest. Like most avid epic fantasy fans, I love a good quest. However, it's been done so often that many quest-focused novels seem like a rehash of Lord of the Rings. For a quest to work it has to have both personal and a wider significance to those going involved - there has to be a reason why the main character would put his/her life at stake to save the world (other than being incredibly brave, or foolhardy).

So, what are the things that turn me off an epic fantasy novels - to the point where I will abandon the book? Unsurprisingly, have a few of these...

• killing off my favourite character(s) - this is very upsetting, especially if I have invested a lot of time into reading a book or series
• overly simplistic plots or character motivations - there are so many shades of grey in life and a good novel should reflect this. Readers like people and events that are not what they seem
• one-dimensional characters that behave the same way throughout the book - these are boring (and all too common in fantasy I'm afraid). I might be reading about a make-believe world but I want characters I can believe in
• sub-plots that take me off in long-winded digressions from the central story, focusing on characters we don't care about - the writer might have a grand plan, and such digressions will make sense in Book Four of the series; however I feel these weaken a story rather than add to it
• any book that rehashes the classics - I loved Lord of the Rings, The Sword of Shannara, Magician and Game of Thrones - but I don't want to read an imitation
• books that deliver beautiful description, but lack substance - readers want action, conflict and drama, not page-long, sigh-inducing descriptions of mist-covered mountains!

What do you love (or loathe) about epic fantasy? Please share!