A good crescendo is hard to come by. A good decrescendo is even harder.
Most students will define crescendo as “getting louder”, and they intuitively know that that means you start soft. I’ve been emphasizing with a lot my students that the point of a crescendo is not so much the beginning or ending dynamic. It’s the ‘getting’ part.
The joy of a crescendo is the journey from one dynamic to the other.
The ‘getting’ isn’t a means to an end. The music is in the journey.
"Modern performers seem to regard their performances as texts rather than acts, and to prepare for them with the same goal as present-day textual editors: to clear away accretions. Not that this is not a laudable and necessary step; but what is an ultimate step for an editor should be only a first step for a performer, as the very temporal relationship between the functions of editing and performing already suggests." -Richard Taruskin, Text and Act