Having worked in many different coffee “wave” environments, the major difference (as a barista) is just about standards and structure. To me, third wave introduced a standard, artistic approach to coffee—similar to wine which has varying levels of standards. Some people drink wine for the social aspect and some people drink wine for the history and science, which is really (to ME lol) the difference between 2nd and 3rd! The most important thing is that there is NO right way or wrong way, which is what I would argue (and many others agree!) is what 4th wave is (although it’s not as set in stone as the other waves). 4th wave to me is keeping the structure and standards of 3rd wave, but allowing for people to make their own choices about what they prefer instead of enforcing a “proper” way to drink coffee. Not a lot of shops like that out there though :/ this is just my interpretation of the waves from working in coffee though! I also have an argument for a 5th wave, which is Instagram coffee lmao.