it's okay what

Don't know why most people who drink double espresso before they say it's very bitter.When i drink that time i feel just okay and does not need to add any sugar in it.when i order that time the waitress tell me that double espresso is bitter that time just like something warned me.I'm will continue seeking for the bittiest double espresso because different place,different people will have different taste of double espresso.Maybe i should go to the place which only selling coffee.Because last week i drank the double espresso in Deliference.