You don't serve wine that way, so don't serve beer that way. Today's beers have loads of flavor, and the colder they're served, the less those flavors will reveal them- selves. If necessary, you can always chill a glass for a customer. Don't use a screwdriver to pound nails. Just as red and white wines have their own glasses, so do ales and lagers.
Nothing ruins the flavor and appearance of beer like a soapy glass.
If you don't keep your rinse water warm and clean, don't expect beer fans to flock to your door. Handle with care. When pouring draft beer, aim for a two-finger head. If the beer is pouring heady, let it settle rather than dump the head off. The stuff is expensive, so don't pour profits down the drain.