Flash can easily run fast enough to observe the movement of lightning(he can technically go FTL and time travel)
He has some comic-type dimension he taps into, to avoid pesky things like physics. So he could probably launch himself out into space. Although most versions can’t run if he can’t step on something. So he’d be screwed.
No, people who commonly do bad things, will often justify it to themselves and others by thinking most people do the same thing. And despite their loud protesting and arguing, they’re pretty much always wrong.
I’ve heard more than one petty thief confidently claim that “everyone” steals something like a candybar when they go to the store. And it’s why there are so many stories of cheaters accusing their partner of cheating.