When trying to express something without specifying it, using the phrase "you know what" can be a helpful way to communicate without giving too much information. However, if you're looking for alternative phrases to spice up your conversations, there are several synonyms you can use. Some include "that thing," "the thing we talked about," or simply "it." For more casual conversations, you could use phrases like "the deal," "the scoop," or "the lowdown." Alternatively, if you want to be more descriptive, consider using phrases such as "the topic at hand," "the issue we're discussing," or "the matter we're looking at." With these alternative phrases, you can keep your conversations fresh and interesting.