Has it ever happened to you, that you are merrily eating your canned soup, until you read the instructions and find out, that you are supposed to add another can of water to it?

No.

Not with (canned) soup, no.
With noodles, yes.

No, but I have a similar story.

My dad and I were eating a boston cream pie. We ate most of it until I found the box it came from and said that it was to be defrosted before eating. Maybe even to cook in the oven for a couple of minutes.

If you enjoy your meal who is to say that you are making a mistake. If you liked your soup then enjoy.
Most discoveries come from mistakes. If we are perfect then we would never advance as a species.

No. I look at the can in the store and I mainly buy canned soup that you’re supposed to add a can of water. I usually add ½ can in order to enhance the flavor of the soup. I don’t buy a lot of canned soups as I prefer to make my soup from scratch so I know what is going into it and how much broth suits my own personal taste (or that of my family). I keep a few cans in the cabinet for those days I’m under the weather and it is easier to open a can that explain to someone else how to cook from scratch.

No, but I witnessed my husband do it when we were dating. He also made ramen noodle with about half the water and it was just noodles no broth.

I don’t see how you can’t know, it’s usually so salty. Unless, maybe you were eating a low salt can of soup.

The amount of nutrients, salt and what-have-you are still the same…
When I make Ramen I use two packets of noodles, and 1 packet of soup mix broth stuff and about one quart of water to cook it in. Before eating I pour out most of the broth.

I make ramen just like kritiper. There is so little liquid I actually eat top ramen off a plate. And I put in the packet when the water comes to a boil, before adding the noodles. I also cover it in parmesan cheese (the Kraft kind that is like powder).

I had a buddy in college that would add the packet of seasoning after draining the water. It was insanity. I tried taking a bite of his and it was disgusting.

@ragingloli ” ... you are merrily eating your canned soup, until you read the instructions…”

Only at that happy confluence of happenstance where I’ve cracked the can open at the wrong end and feel the desire to read while I suck on it’s tantalising lower lip.

My son adds half milk and half water to tomato soup. Really makes it more robust.

I have to agree with @JLeslie, it’s usually so salty, I can’t stomach it. Even with the water, it’s sometimes still too salty, so I just take a few bites, or maybe ¼ can.