Salt/sodium is obvious in bacon, soy sauce, and many other foods/ingredients. But unless you pore over every label, and I don't think a preponderance of shoppers consistently do, you can wind up consuming a lot more sodium than you estimate you are.
The other day, knowing there's a large, partially-used jar of mandarin orange segments in the fridge, I bought a package of sugar-free instant vanilla pudding mix with the intention of making orange-vanilla pudding. I know, I could make it from scratch, and I do prefer the taste of cooked pudding to instant, but I did not want the leftover egg white, and thought the additional thickeners in the instant would give me better odds of having it set up properly. I want to use the juice/syrup in place of some of the milk.
At home, when I looked at the package, I was surprised that a 4oz serving contains 20% of daily sodium intake. That's a lot for something that does not taste salty.
We know that celery is very high in sodium because we've read it, not tasted it. And please, let's omit the debate about whether or not we should all be trying to avoid consuming a lot of salt. That's a different topic.
What foods/ingredients have surprised you with unexpected salt levels?