Okada vs. Tanahashi is the best. Not a single wasted storytelling and every single match is incredible with callbacks to the previous matches and added layers to up the stakes in the match. I'd put that on any best feud list just due to the evolution of both Okada and Tanahashi's characters throughout the feud. It is long-time storytelling at its finest.

Undertaker vs. Kane had an epic story in 1997 to 1998 when they first initially feuded. From Bad Blood to Wrestlemania XXIV, the segment were truly great television. Arguably the best supernatural wrestling story ever told that wasn't too hokey or over the top. And their match at Wrestlemania XXIV was by far their best match because it had such a good build and everyone was invested. After Wrestlemania their feud dipped in quality. The Inferno match was good visually to see the ropes on fire. But the segments weren't as strong and then the feud ended when they became Brothers of Destruction. When they feud in 2000 leading up to Summerslam it wasn't special and the match sucked. The lead up to Undertaker's return as the Deadman at Wrestlemania XX and haunting Kane was good (if a little hokey at times like the ring shaking), but other than Undertaker's entrance it was a mediocre squash match. And then their last feud in 2010 also sucked with 3 boring matches that just got worse and worse.

Triple H vs. Shawn Michaels overall had a solid enough good. The lead up to Summerslam 2002 with the brief DX reunion and Triple H turning on Shawn was great television. Also attacking him in the parking lot. And that match at Summerslam was an instant classic street fight and by far their best match. Their follow match at Armageddon 2002 in a 3 Stages of Hell Match was long and mediocre. Then they stopped feuding for a year, and they had a fantastic underrated and at times overlooked match on the January 29th 2003 episode of Raw. A pretty great and brutal Last Man Standing match at Royal Rumble 2004. The triple threat match with HHH, HBK and Benoit at Wrestlemania XX is a classic and one of the best triple threat matches of all time, followed by another fantastic triple threat match at Backlash the next month that sometimes gets overshadowed because the first match is so epic. And their final match in the rivalry at Bad Bad 2004 in Hell in a Cell is mostly a good match, but overlong, indulgent and quite boring in large sections of the match.