It is a pet peeve of mine, but any statement that implies that Unix time is a count of seconds since epoch is annoyingly misleading and perpetuates such misconception. Imho better mental model for Unix time is that has two parts, days since epoch * 86400, and seconds since midnight, which get added together.
How is it misleading? The source code of UNIX literally has time as a variable of seconds that increments every second.
But it's correct. It's "a" count. Just not the count that you might always expect. And the "second" in this definition means what people usually understand as a second, as in the duration is always the same. That's all, and it's pretty useful imho.