When I hosted my friend S way back in the 1990's for her first visit to the Philippines, she was aghast at how much we used sauces, dousing our foods in ketchup or soy sauce or patis with garlic or chilli. Having lived in China for more than a year by then, she could see the similarities and influences, but she didn't quite understand why there was a need to add a layer of flavor to something.
I think of S at times when having a meal and mixing up a side sauce, usually soy sauce or fish sauce, a paste of garlic or a squeeze of calamansi. When I know something might be a bit on the bland side, a crushed Thai bird-eye chilli always helps. For a simple meal of tofu and rice, I mix sesame oil, ginger and a light soy sauce to keep me from losing interest in what I am eating. I guess a good side sauce is to highlight flavors or textures and to avoid gustatory malcontentment.
Inspired by a recent online recipe for nuoc mam, the Vietnamese fish sauce spiced with chillis and herbs, I ground a paste of garlic and a Thai bird-eye chilli with some salt, added it to a liquid blend of fish bagoong (that uber-pungent fermented soup, which looks less than appetizing in its grey sludge), patis (yes, that's three sources of salt), vinegar, calamansi, and a fresh jalapeno sliced in two. So that makes three salty flavors, two spices, and two souring agents. Oh and don't forget the garlic. I left the blend in the refrigerator overnight and tested it on my dinner of sauteed pork and rice. It's hot, salty but doesn't make my mouth itch, and savoury. This could be addicting.