There are some things that most of your clients of any age can probably agree on. For example, burpees are unpleasant yet satisfying, and a playlist that includes Beyoncé can make just about any workout fly by. But you might find that your millennial clients don’t quite understand the elegance of a grapevine maneuver or that your baby boomer–age members are mystified by millennials’ desire to post sweaty selfies.   As much as there has been a generational melding—particularly when…