It is important that characters in a superhero comic never become overindulgent. Yes, under most circumstances, it would be amazing to have superpowers or an indestructible suit of armor or all the monies, but to just throw awesome shit onto a blank slate is not creating a character; it's creating a fantasy. This is why I'm never going to get into Batman. He is a dark, brooding character for no reason, with a bunch of money, and a handsome, genius ninja. His superhero persona is more of an escape from the overly-awesome regular life he leads.
Quicksilver, on the other hand, is living in constant pain.
Let's back up. Again, it is pretty awesome to have superpowers, but those powers have to come at a price. Quicksilver of course has super speed, but instead of this being dressed up as being totally awesome, it is a curse, and it makes him miserable.
One of the best Quicksilver scenes I ever read was him talking to a psychiatrist about how awful it is to be him, even though it really never came up in the comics before. He was always kind of a dick on the one hand, and constantly crossing the line between hero and villain. This becomes apparent in almost every "alternate reality" version of Quicksilver, where he always has a 50/50 chance of being a hero or a villain. In the newest X-Men film, he's an amoral asshole. In some TV shows, he's a total asshole and an antagonist. In some of the alternate realities, he's a bastion of hope. In others, a complete psychopath. Even in the main Marvel comic universe, he starts off as a villain, and only later becomes a hero. Even now, his attitude towards heroism is more apathetic than anything else.
But that's really nothing, there's a lot of characters who are dicks and a lot of character who play the anti-hero role, and even a lot of characters who skirt back and forth between heroism and villainy. What makes Quicksilver special is that this is a direct consequence of his powers. Going back to that conversation he had with the psychiatrist, he mentions that his life is like waiting in line at the bank. People wonder why he has such a hard time connecting with everyone, and why he's a total asshole to everyone he meets, and he explains that it's because he is spending his entire life waiting. His super speed makes it so that moving at a normal person's pace is agony for him.