Neither can I.
Hawkguy. That is a perfect exemple of how you can ruin a character on the long run just to profit on the short run (and, honestly, David Aja's art was the only reason that run is special).
That is basically it. The point is, bad writing is what separates a crappy retcon from a good development of the character. Let's take, for exemple, Wanda and Pietros's progenitors. At first, a couple of Gypsy orphans, rescued by Magneto. Then, the offspring of Golden Age super-heroes Whizzer (from which Pietro inherited his speed) and Miss America (from whom Wanda got her brown hair), and it was even explained howthey endedup living with Gypsies. And then, Byrne dropped a hint in Uncanny X-Men, showing that Magneto had the same white hair Pietro did, and that his late wife, Magda, was the spitting image of Wanda, and Bill Mantlo (I'm not 100% sure it was him) followed through in his Vision and Scarlet Witch mini-series, explaining how they got to Wundagore Mountain and then to the Maximoffs. Later, they no longer were mutants and were actually creations of the High Evolutionary. However, from what I recall, very little was done to explain how this affected all these connections. Now, I think they are mutants again, but I'm really not sure what their family tree looks like at this point. So, how much of that was actually character development, and how much was bad retcons? The first cases took care to cover their bases, tieing events one to another, not negating anything (however, it does make Magneto's abuse of his own children VERY creepy, and not at all forgivable and forgetable, though, if you take in consideration Xavier's own thoughts whhen the minor Jean Grey joins the X-Men, you'll undertand that it was a time much more tolarable with certain things WE may find creepy). The last one was motivated purely by a business angle, and not by a creative necessity, and IMHO, that makes it much less acceptable. There are many "retcons" that may not be good, but they originate from the point of view of a creator that something needs to be corrected, be it because it opens up new story possíbilities, it redeems the character from something that, in the writer's opinion, makes him look bad, or to undo something that was, once again in the opinion of the writer, it undoes a creative decision he disagrees with. (Exemples: Brubakers Winter Soldier for the first, Byrne stating that the Dr. Doom that faced the X-Men with Arcade as an ally was a Doombot, because, in his opinion, Doom would never accept to be treated as Arcade treated him, or Jim Starlin comming up with clones to explain the way Thanos behaved differently when he wasn't writing him, for the second. And Busiek sort of undoing Byrne's explanation that the Vision was not the original Human Torch, but made of his spare parts, in Avengers Forever.) Those, I can accept, even when I dont particularly agree with them. It's those retcons that don't seem to be about the character, but for some other reason (pump up other flavor of the month characters at the expense of an established one, editorial mandate for whatever reason it may be, commercial decisions, etc...) that really bug me.
Peace