“Performance Issues” (The Avengers)

During the final battle in 2012’s The Avengers – the Battle of New York, as it’s known – Tony Stark confronted Loki at the top of Stark Tower, sans his Iron Man armour.
He casually poured himself a drink and offered the God of Mischief one, whilst also threatening him with the combined might of his fellow heroes. Loki laughed off the threat by saying the Avengers would be too busy fighting against Stark to be bothered about what he was doing, then used his sceptre in an attempt to mind-control Stark into becoming his slave.
The sceptre hit Stark’s arc reactor, rather than his actual body and, as a result, its mind-controlling powers didn’t work. A surprised and disappointed Loki said “this usually works” and Stark humorously compared the situation to sexual impotence, saying “well, performance issues. It’s not uncommon. One out of five…” – and that didn’t sit well with Loki at all.
