One of the things that often comes up for people during meditation, is the difficulty of just allowing the breath to be however it is while simply observing it. There’s a strong tendency to mess with the breath somehow, especially because it often seems to change, all by itself, when you’re observing it. One minute, it might be nice and smooth, and then the next minute, it turns all choppy or raspy, and you think, ‘hey, what happened! I want my breath to stay nice and smooth!”
But, if you can resist the urge to monkey with your breath when you notice it changing in this way, it’s a golden opportunity to catch a glimpse of something really important and fundamental.