The sauce was brainless to put together. Good sauces often seem very tricky; I can't imagine doing marinara from scratch better than from a jar, and anything involving simmering has much to large a chance to fail. This particular sauce, however, was fairly easy to do. Because Trader Joe's doesn't carry canned pineapple, I was short on its syrup, but I put together what juice I could extract from the spears, syrup, bbq sauce, vinegar, brown sugar, and soy sauce. Very easy because there's no point of no return: taste a little, adjust as needed. I ended up adding quite a bit more vinegar than I thought I'd need.
For the actual contents of the meal, I chopped up a few different vegetables, the pineapple spears, and a small piece of chicken.
Some of the onions, some of the pineapple, the chicken, and carrots went in first to be cooked some, then stirred in the sauce and left to simmer and soak in some of the flavor. I actually ended up having far too much sauce and needed to drain it back out since it wasn't boiling away very quickly, but I found myself with a very colorful mix after adding the last of the pineapple, onions, and green bell peppers, plus some red pepper flakes to kick.
I put it over rice, using the extra sauce to flavor the rice, and loved it. In retrospect, it was really just a mix of a bunch of colorful and tasty items into a sweet & sour & salty dish. Maybe not too impressive, but I'm proud of myself for having added sweet & sour to my stir-fry repertoire. Now to find bitter...