#2. Eddie Guerrero vs Rey Mysterio

It's a shame that we have to put two legends of the highest caliber on this list. Rey Mysterio and Eddie Guerrero had a big history together and they even faced off that year at WrestleMania 20 while being the Tag Team Champions.
However, WrestleMania was a "friendly match", while SummerSlam was a grudge match of the highest order. We've seen Eddie Guerrero as one of the greatest babyfaces in WWE history, but we've also seen the vicious heel side of him.
Whichever side he aligned with, he always did his best to get over and managed to do so successfully in 2005 as well. However, the feud with Mysterio in the summer of that year took a weird turn as Guerrero claimed to be the biological father of Mysterio's son Dominick.
They would have a ladder match at SummerSlam 2005, where the stipulation was that the winner would get custody of Dominick. Vickie Guerrero had a late run-in and the match itself was a big disappointment.
While Guerrero is deservedly one of the most celebrated Superstars in WWE history, this was a forgettable feud and one that WWE won't be acknowledging any time soon.
Becky Lynch has been challenged HERE.