The phrase is well known, and has its origins in a time when salt was very valuable - wages were even paid with it. I wasn't raised eating a lot of it, so I don't really have much of a taste for it.
I recently visited my younger sister at her college, and made her pancakes after her early morning class. That is, I attempted to make pancakes -- Karen and I bought flour, eggs, milk, and syrup, but forgot the salt and sugar. From experience, I knew the sugar to be a minor loss, but I had never made pancakes without any salt. I had assumed that the salt provided a bit of flavor, and helped out by adding a little iodine to the diet.
This assumption proved faulty - all the pancakes came out as flat as a, well, pancake. No, that's not right - they were even more flat than that. They were edible, and even tasty with a bit of fake maple syrup, but it just wasn't quite right.
Having made bread before, I know that salt is important to help limit the growth of yeast, but I've successfully skipped it before out of laziness. And I've boiled pasta, where the salt is explicitly optional.
Pancakes though – not an option. We asked around, and managed to find someone with coarsely ground sea salt - it looked weird, but with just a pinch of that mixed into the remaining batter, all was well.