I just looove sweet and sour sauce, it reminds me of the evenings when my mom cooked "Asian" ahah (well, she bought an industrial sweet and sour sauce and Cantonese rice from the caterer, but I really loved it).
And I just realized that it's easy to make, super quick, and inexpensive.
I mainly use it to make sweet and sour tofu, cooked with vegetables and served over rice. But you can also use it for dipping spring rolls or adding it to all your stir-fries. It would be interesting to try it on tempeh, for making banh-mi sandwiches, for example ;)