I've been serving for about 10 years, but I still struggle with this complaint. The best I can do is offer them an extra shot (which costs the same amount as a cocktail at my restaurant… we have no "floaters" or add-on options besides making something a double) or using less mixer. Neither of these satisfy some guests, as they don't want to pay extra for a drink they consider acceptable, or they're unhappy with having less liquid in their glass. The only thing they seem to want is more alcohol for free, but they're unhappy with being told "no," which is the only answer to that. How do you successfully approach these guests?