I will answer this question by saying that it all depends on how you look at the term "kayfabe", and you would classify someone as breaking it. When I first became a WWE fan in 2003, I heard everybody criticizing me for watching something that was... "fake". I heard all of that but at 9 years old, I didn't have internet, I didn't know what was real and what was fake... I couldn't back myself up.
That was until I was about 11. My mom bought me this video tape. I thought it was actually wrestling with superstars, you know... wrestling! But it was titled, "Wrestling's Biggest Secrets Revealed". It taught me about juicing/blading, how the backbreaker is done, the legdrop, crossbody, and a whole bunch of other stuff. That really did not effect how I looked at wrestling until around 2007. That's when I started to notice things during a match that I never noticed before, and I felt it was kinda cool... I felt like I was part of the business, although I would need to learn so much more.
As for kayfabe, breaking it can cause me to get a little annoyed, although at any times, I find it to be very entertaining. Fueds that break kayfabe and bring in someone's personal life into it makes it seem more like a fued, which I like. Some examples of that include the 2006 fued between Ric Flair and Mick Foley. It was actually real-life, it was partly based on each of their books, and they really hated each other... the intensity was awesome! Also the Hardys fued that occured broke kayfave. It included Jeff's drug problems, his burned down house (although it was on WWE.com), the death of his dog... all personal.
However, the one thing about breaking kayfabe that I hate would have to be heel/face turns. I understand that WWE has to change a superstar sometimes but I hate to see a face-turned-heel become friends with a heel that they made a career on fueding with, or vice versa. A good example would be Kane. He was a face until mid-2008, but when he turned heel, WWE made him team up with M.V.P. We all know about their late-2007 fued where Kane set MVP on fire. If I were in creative or M.V.P. himself, I would not have them team ever, and I would not forgive some monster who caused me to have 3rd degree burns on my back. Same with Matt Hardy and Edge. Matt turned heel and during a 10-man tag match where he had 3 other partners to tag in, but chose edge, despite the long fued they had over Lita and whatnot. Also, John Morrison. He teamed with Cryme Tyme with any problems. Remember that Dirt Sheet vs. Word Up fued that occured during the closing part of 2008?
So, yeah... I wonder why WWE doesn't allow things to seem a little more real, even if we all know it's entertainment. Some storylines were never meant to be broken, but knowing WWE, they make bad decisions all the time.