If you're referring to water, bring your own bottle. That's why there are water coolers at the gates...

If you are referring to drinks, there was once I was rushing to finish my drink at the gate (it was like less than 15 min before departure), and the gate agent actually told me to take my time to finish my hot drink, they will wait for me.

If this is not service, then I don't know what is. Are you expecting to have your drink in the plane??