Activity diagrams show the potential areas of concurrency, but have nothing to say about whether these areas are worth exploiting. For example, in the piña colada example, a bartender would need five hands to be able to run all the potential initial tasks at once. And that’s where the design part comes in. When we look at the activities, we realize that number 8, liquify, will take a minute. During that time, our bartender can get the glasses and umbrellas (activities 10 and 11) and probably still have time to serve another customer.
This is more annoying than have the computer do it
