If somehow the two had met during one of Austin's 1998/1999 title runs (I think late-1998 would have been best, since Shamrock had just won the King Of The Ring in June, and could have benefited from a heel turn and strong push against Austin late in the year), this imo could have been a pretty good rivalry. Really one of the only promising feuds that could have taken place during the Attitude Era that never did. Just pretend there's some alternate universe where all the Austin/Taker/Kane stuff had ended at Breakdown in September with Austin walking away from the triple-threat/handicap match with the championship (and I'm clearly not saying this would have been a better creative direction than what we got - Deadly Games tournament, Rock as corporate champ, Rock/Mankind rivalry, etc. - I'm just being hypothetical here), a rivalry between them could have been good for a few reasons: 1. They were both bad-ass, intense individuals, and Austin being a major asskicker and Shamrock having a tendency to snap and hurt someone at a moment's notice would have led to some cool shit between them. I'm talking about finding each other and brawling at other locations outside of the arena and stuff, too. 2. The Toughest S.O.B. In The WWF vs The World's Most Dangerous Man would have been a great match moniker. 3. Austin famously refused to give up at WM13 (in a match where, funnily enough, Shamrock was the special referee), which is how he earned the "toughest S.O.B." nickname in the first place. You could have Shamrock promise to hurt Stone Cold so bad that he would break his spirit and force him to give in to the pain by tapping out. I certainly wouldn't call it a huge missed opportunity or anything, but it is a slight disappointment that we didn't get at least 1-2 month program between them in there at some point. And no, some random match on Raw doesn't count. I'm talking about an actual, drawn-out angle.