I don't plan my sets either, have in my mind some I may want to spin but you never know how the night will pan out and what is required and how receptive the crowd is to certain types of records.
Waffle? I never said owt about waffling, I don't want to hear DJ's waffle on and on but there should be some interaction between DJ and dancers rather than just playing record after record which anyone can do, and with a bit of practise make it flow.
The knack is the interatction and still making the set flow. As I said I think most dancers would want a slight breather now and then, mop their brows with their beer towel and maybe a quick drink