"Data dominates. If you've chosen the right data structures and organized things well, the algorithms will almost always be self-evident. Data structures, not algorithms, are central to programming." - Rob Pike, "Rules of Programming"
And to be clear, I am making a distinction between the essence of "programming" and the essence of a "program". I agree that with Rob Pike that (and to quote myself) "The purpose of a program is, and ought to be, something that transforms data into other forms of data".
or, from ~15 years earlier, with vocabulary to match: "Show me your flowcharts, and conceal your tables, and I shall continue to be mystified; show me your tables and I won’t usually need your flowcharts: they’ll be obvious."
The essence of programming is data.