In an interview in the Paris Review, Gabriel Garcia Marquez said:

The first line [of Kafka's Metamorphosis] reads "As Gregor Samsa awoke that morning from uneasy dreams, he found himself transformed in his bed into a gigantic insect..." When I read the line I thought to myself that I didn't know anyone was allowed to to write things like that. If I had known, I would have started writing a long time ago.

I love this passage for many reasons. One is that notion of "I didnt know anyone was allowed" which describes perfectly that sense, as you lean into your years of self-examination, that there are these piles of rules you inherited and now you must decide which are sensible and which others are meant to be shattered. The latter rules are the ones, that by breaking, allow you to become more yourself.

Garcia Marquez, a brilliant student of this process, went on to become one of the masters of the opening line:

Many years later, as he faced the firing squad, Colonel Aureliano Buendía was to remember that distant afternoon when his father took him to discover ice.
-from One Hundred Years of Solitude

It was inevitable: the scent of bitter almonds always reminded him of the fate of unrequited love
-from Love in the Time of Cholera

And,

Jose Palacios, his oldest servant, found him floating naked with his eyes open in the purifying waters of his bath and thought he had drowned. He knew this was one of the many ways the General meditated, but the ecstasy in which he lay drifting seemed that of a man no longer of this world.
-from The General in his Labyrinth