Is it a good thing that I can tell there is no salt in certain foods?

It would be better if you could not tell the dish was missing salt. However, too much salt on a persons diet is unhealthy. I seldom use more than a small pinch of salt when cooking. You can always add salt and so can your family or guests, but you can't take it out.

You will probably not like me for this, but seasoning in foods starts with salt. Salt is not going to kill you, new studies have shown that salt and it's relation to heart problems and high blood pressure need to be re-evaluated. Researchers as we speak are doing studies on sodium and heart issues.

Unsalted - unseasoned food, sucks. People do over-salt - usually their own food or are consuming a lot of fast food, frozen meals, TV dinners, pizzas etc there is a lot of sodium that is added as 'flavor enhancers' the doesn't taste 'salty' but is salt based and they use a lot of it.

I would say it's good that you can tell there is no salt in a dish, but at the same time, the dish probably needs it. Tomatoes naturally have a lot of sodium and oftentimes need a bit less salt, or careful attention to how much you are adding.