The purpose of salt in cooking is as a flavour enhancer. It brings out the other flavours that already exist in the food. Salt is not a flavour. It's why a lot of recipes call for salt to taste, as how much you add can vary a bit. Next time you cook something that tastes a bit dull, try adding a small amount of salt and note what it does to the flavours as you add more. If it tastes "salty" you probably added too much.

Source - I was a chef/cook for 9 years