As luck would have it, the antonyms for this phrase are numerous. One could say, "Unluckily," "Unfortunately," or "Regrettably." Other possible antonyms for this phrase might include "by design," "by intention," or "by choice." Each of these expressions reflects a different perspective on the events that have occurred, and each one suggests a different attitude towards them. Whether we view our experiences as random, controlled by fate, or influenced by our own actions, there are always different ways to express our feelings and thoughts about them. Ultimately, it is up to us to choose the words that best reflect our perspective on the world around us.