To wit, Coulson and Sitwell not only use Tony Stark to trick General Ross into not allowing the Abomination on The Avengers, but Tony buys Ross' favorite bar and has it demolished for being an enormous dickwad.
A Funny Thing Happened on the Way to Thor's Hammer
Agent Coulson stops at a fuel station, just as two thugs are holding it up. Pretending to be a coward, he slides his gun over to one of the thugs and as he goes to pick it up, Coulson throws a bag of flour at the other miscreant, then using one of the shelves, he jumps up and kicks the first thug's shotgun downwards (obliterating his foot), then grabs said gun and knocks them both out. He leaves shortly thereafter, but not before casually apologising to the woman for the mess, and paying for the donuts he'd wanted to buy. Both powdered sugar and chocolate. He couldn't decide.
Sitwell's efforts to capture Benny and Claire during which he fights Benny quite well.
Likewise Sitwell's decision to have Benny and Claire join SHIELD when he finds out that Benny made the gun work.
This short clip shows us that Peggy is definitely not just a pretty face, as she effortlessly defeats several henchmen, even tossing one through a window.
The fact that Peggy completes a mission meant for 3-5 agents by herself.
"Learn to count."
After finishing the mission and collecting the 'Zodiac', Peggy gets a talking to by Agent Flynn who chastises her for doing the mission alone and claims they don't need her in the agency. Seconds after this, Flynn gets a call from Howard Stark who tells him that Peggy's being promoted to co-running SHIELD with him, and that when Flynn tells her this, he's to tell her how honored he is to do so.
Flynn offers to carry her stuff. Peggy's response could not be better:
Peggy:(calmly) Thank you, Agent Flynn, but as has always been the case, I do not require your help.
On a meta note, just the fact that it was even made. Hayley Atwell was certainly pleased about it, as evidenced by this quote.
Another meta-example: the short was successful enough to springboard into a TV show.
All Hail The King
Jackson Norriss sneaks a gun into Seagate Prison by hiding it in his camera. Immediately after it deploys, he kills every guard in the room.
Trevor's friend Herman takes a bullet to the shoulder and keeps fighting! Shame he didn't win, though.