I will not go into how I feel
Some days before, he had received from Brazil a stamped, registered package. It was a book, an octavo volume. Ashe left it in the bar where, months later, I found it. I began to leaf through it and felt a sudden curious lightheadedness, which I will not go into, since this is the story, not of my particular emotions, but of Uqbar and Tlön and Orbis Tertius.
There's a lesson here for beginning writers, who on the whole always do stop and go into their or their characters' emotions instead of remaining disciplined and focused on the story they have chosen. Except that Borges, in his brazen way, goes on in the very next sentence:
In the Islamic world, there is one night, called the Night of Nights, on which the secret gates of the sky open wide and the water in the water jugs tastes sweeter; if those gates were to open, I would not feel what I felt that afternoon.
You can break any rule, even one you've just put forward, if you do it well...