If only I knew everything in this world I would have been god bartender and not a professional Bartender. Thanks for the observation and thanks for writing in I really appreciate it.
Now coming to your question we as professionals having spent a decent amount of time in the beverage trade and over a period of time have some instincts that gives us the edge over some of our judges who are from different trades. Having said that I would also like to say that every professional too will have his own ideas. To me the way I look at it is very simple. Taste is very individual therefore what is good tasting to me may be bad tasting for someone else. I always look at the balance of the drink i.e. not too sweet not to dry and not too alcoholic in nature.