Define a career in four matches

Ok, I'll just focus it more on his WWF/E run, but Steve Austin

Austin beats Jake Roberts to win King of the Ring, and in his 'coronation' gives the Austin 3:16 speech that will really kick off the rise of Stone Cold

Austin looses the Bret Hart at WrestleMania 13 in the I Quit Match. Between Hart's heelish acts in the match, and Austin refusing to tap out, instead passing out, they managed to pull a double turn perfectly, and started up the engines to really begin the rise of the Austin era, to the next level.

Austin beats Shawn Michaels to win the WWF Title at WrestleMania 14. Austin officially becomes the man, and gets really put out into the main stream, with Mike Tyson's involvement in the match. And the build up to the match, as well as the immediate aftermath sparks the beginning of the Austin/McMahon feud.

Austin loses to the Rock at WrestleMania 19. The end of the era. The end, of not only one of the feuds that fueled the Attitude Era, but of Austin's in ring career.

for Hogan mine would be almost same:

Hogan beats Iron Sheik for the WWF title - the birth of Hulkamania

Hogan slam Andre at WM3 - Ultimate hype match, Hogan beats the unbeatable by doing the unthinkable: body slamming the Giant.

Hogan loses to the Ultimate Warrior at WM6 - The Two BEST clashed, the crowd went insane, the "torch was passed".

Hogan is the third man at Bash at the Beach - the most famous heel turn ever, rejuvenated a fading career, swung the balance in the Monday Night Wars, and of course birth of the nWo, one of the most influential and successful factions of all time.

Ultimate Warrior

Vs Honkytonk Man, Summerslam 1988. Ends the longest IC title reign in 40 seconds.

Vs Hulk Hogan, Wrestlemania VI

Vs Randy Savage, Wrestlemania VII

with Hulk Hogan vs General Adnan, Sgt Slaughter & Col Mustafa, Summerslam 1991. When he was fired after this match and Hogan left to film movies, it marked the end of the Hulkamania Era.

Sting

Iron-Man match vs Flair at Clash of Champions '88

World Championship match vs Flair at Great American Bash '90

World Championship match vs Hogan Starrcade '97

Closing out WCW vs Flair at the Panama City Nitro
(Or WrestleMania vs Triple H if you wanted to say a WWE WrestleMania appearance)

No Wrestlemania XXX vs Brock Lesnar?

Goldberg;

Vs Hugh Morrus, Monday Nitro Sep 1997

Vs Hollywood Hulk Hogan, Monday Nitro Jul 1998

Vs Kevin Nash, Starrcade 1998

Vs Brock Lesnar, Survivor Series 2016

CM Punk

CM Punk Vs Justin Credible - ECW TV - The debut of the man who would go on to reshape the way people thought of "indy wrestlers" in terms of how much they could succeed in the WWE

Team DX Vs Team Rated RKO - Survivor Series 2006 - On a team also featuring Triple H, Shawn Michaels and the Hardys, Punk received the biggest reaction on the team.

CM Punk Vs John Cena - Money In The Bank 2011 - Punk's "Crowning moment" in the WWE

Royal Rumble Match - Royal Rumble 2014 - For obvious reasons, The last wrestling appearance for CM Punk.

Like your choices too, and 2 of the 4 were actually ones I considered, but didn't for a couple reasons.

- SS vs Demolition: I felt the Bulldogs win was more important because at the time it felt like Vince wasn't really invested in the Harts, but once he put the Belts on them they ran with it, and made their WWF careers. With the Demo win, it seemed more like they were just transitional Champions, either with the first booking plan ( losing it back to Demolition, til Vince soured on them ), or the second ( losing it to the Rockers, which did happen. Only a technical issue kept the belts with the Harts ). That whole reign felt kinda wasted to me.

- vs Flair. I know, you'd think his first World Title win would be an automatic. But the way the WWF did it, and then never showing it on tv . . . It kinda felt like an afterthought compared to the ongoing Megamaniacs vs Flair and Razor drama. I feelt the WM X win did more for his career,as the show was pretty much about the Hitman in both defeat and victory. After his 2nd Title win, there was no doubt he was the man.

As far as the other 2 :

vs Piper was great, best match at that Mania hands down. But it honestly did nothing for his career at the time. He was the mid card guy who,was dependable to have a great match with anyone before he went in,and was in the same spot going out. If anything, I'd argue his match with Bulldog at SummerSlam 92 meant more, as he truly main evented a PPV for,the first time, and showed he could handle it.

vs Austin I briefly considered, but I feel that would be more of a defining moment for Austin than Bret.

Backstage segment with Armando Estrada - ECW TV - July 8th, 2008: The on-screen debut of the biggest acquisition to the WWE since Rocky Miavia.

Vs. Armando Estrada - ECW TV - July 8th, 2008: The in-ring debut and the biggest win in his career. Scoring a pinfall over a former ECW General Manager and ECW Legend. His performance in this match showed what was to come in his long lasting WWE career.

Backstage segment with Matt Hardy - ECW TV - August 5th, 2008: Sharing on air time with a former ECW Champion and for World Champion, Matt Hardy. Hardy even made sure he was welcome in the WWE. This moment right here solidified him as a top guy within the WWE.

Vs. James Curtis - ECW TV - August 8th, 2008: Unfortunately his final appearance in the WWE, but hands down one of the greatest matches. Not only in WWE history, but pro-wrestling history. There will never be anyone like him.

want to say braden walker