A man goes out drinking every night, returning to his home in the wee hours of every morning. No matter how much he drinks, he never gets a hangover. This drink is very well known, but is rarely consumed, served warm and taken straight from its source. The man is a sucker for a free drink, especially since he can't live without it. What is his favorite drink?

“Blood”

While blood is indeed the favorite drink of a vampire, the riddle specifically describes a man who drinks every night and never gets a hangover. The focus on a man suggests a more playful interpretation rather than a literal drink.

“Wine”

Wine is often associated with drinking and can be served warm, but it does not fit the description of being taken straight from a source nor does it relate to the concept of being a 'sucker' for a free drink in the context of the riddle.

“Coffee”

Coffee is a common drink that can be consumed nightly and served warm, but it doesn't align with the characteristics of a vampire or the idea of never getting a hangover, which hints at an immortal being.