I love umami flavors (fish sauce, msg, etc.) so I think I can recognize it pretty easily if I taste it.
Tonight, I had steamed artichokes with a little olive oil, lemon juice, and fleur de sel, dipped in Fage's greek yogurt.
Once I finished the artichoke, I had about a half cup of yogurt left over, so I squeezed in some lemon juice, sprinkled on some fleur de sel, stirred it up, and voila! A taste that was new, yet slightly familiar.
I swear it activated the same part of my mouth/taste buds/brain that fish sauce does.