The antonyms for the phrase "one sweet time" are numerous and can vary depending on the context. Some of the main antonyms could relate to the amount of time involved, the quality of the time spent, or the nature of the experience. For example, antonyms could include 'hurry' or 'rush,' implying a lack of time, 'unpleasant' or 'bitter,' referring to negative experiences, or 'brief' or 'short,' suggesting a lack of duration. In some situations, antonyms could also refer to the pace of time, with phrases like 'hectic' or 'chaotic' suggesting a faster pace, while 'leisurely' or 'relaxed' might indicate a more enjoyable pace.