I bet that mud tasted rather salty, and in tasting that saltyness, you've proved that you undoubtedly have a talent. It doesn't need to be useful, or distinct to exist. It's not like light, talent doesn't go out when you switch it off.
no way! each person is always good at something, where other lacks
well, it depends on some/many other factors... (pls explain below)
yes, certainly there is a person with no talent at all!