It does affect the taste of the shisha when you mix more than one flavor with another flavor. But, it affects positively, as it adds more flavors to the overall flavor of the hookah. For example, adding double apple with Mint will surely get the two tastes in one flavor. So, it works that way, but if you don't know which flavor should occupy how much of a portion of the overall flavor, you may get a negative or bad taste from that shisha mix. It will also help you generate huge and thick clouds of smoke that you can enjoy. Finally, some combinations of shisha mix will last longer compared to a single flavor.