The drink-ice cube ratio
Sorry Europeans, but some drinks taste better with ice cubes. The key is to get the ratio right. As a first approximation, there are two main problems. First, the ratio of drink to ice cubes may be too high. In that case you start off by doing some drinking merely as an act of investment in the future quality of the drink. (Ideally I would prefer to pour some drink on the floor, though I am too civilized for that. Alternatively, this can be reason to dine with a companion, who will sop up your excess.) Another reason the ratio becomes too high is if the waiter comes by and pours excess drink into your glass, so that he may take away your can or bottle "too soon" for his own not quite legitimate purposes. This can be avoided by placing your bottle or can in an inconvenient, hard to reach place.
Country restaurants in Thailand sidestep these problems by sending around a staff member to replenish drinks with fresh ice cubes and restore the proper ratio; trust is essential.
Second, the ratio of ice cubes to drink may be too high. If you order two drinks you rarely find (for whatever reason) that both have too many ice cubes. You can put excess ice cubes from your water glass in your Coke but not vice versa. If you order both mineral and plain water two-way transfers are usually possible and thus the tastes of your two drinks end up insufficiently diversified.