So in programming, you’d write ‘if’ as:
not pizza or fart where the farting is irrelevant until the pizza is involved.

While ‘iff’ would be:
pizza equals fart where pizza means fart and no pizza means no fart.

I actually wrote iff as (not pizza and not fart) or (pizza and fart) before, and I’m pretty sure that’s the way I wrote an iff in production code in the past, but your comment made me realize that “they should be true at the same time” can be tested really easily with equality.