Do you enjoy something to the extent that you consider yourself something of an expert? Do you need a simple title for yourself to express that enjoyment? English conveniently offers a long list of nouns you can use to describe what kind of enjoyer you are: aficionado, enthusiast, buff, connoisseur, fanatic, fan, freak, nut. But they aren't all just interchangeable synonyms. Each carries connotations that you may or may not want to identify with.
A connotation is a hard-to-pin down feeling. It arises from a history of use. The words you have seen in combination with a term over the years will color your sense of that term. You can get some insight into word connotation by looking at collocates (words that frequently show up together) in large collections of linguistic data. The Corpus of Contemporary American English (COCA) at Brigham Young University has more more than 520 million words of text (since 1990) and includes both spoken English and texts from fiction, magazines, newspapers, and academic journals.
I used COCA to find out which words were most strongly associated with "enjoyer" terms in phrases of the "X ENJOYER" type, yielding terms like cigar aficionado, aviation enthusiast, and fitness buff. For each term I took the top 10 most frequently occurring pairs, and then ranked them by Mutual Information (MI) score. The MI score is basically a measure of strongly linked the two words are. Here are the results.
The most frequent collocate in front of aficionado is cigar, and it also has the highest MI score. The magazine Cigar Aficionado plays a big part in this result, but it fits with the general vibe represented by the rest of the collocates (jazz, architecture, fashion, baseball, wine, gun, film, music, and art): macho culturedness. Aficionado is for when you enjoy something with swagger and money.
Although art and wine show up again here, enthusiast carries an overall flavor of machinery on its list with aviation, auto, computer, gun, and car. It highlights knowledge of facts, trivia, and mechanical explanations.
Connoisseur is not a very common word in English, but if you like wine you're probably going to see it. Connoisseur seems to be associated with things you taste—cigar, dessert, cocktail, beer, coffee. While wine aficionado and wine enthusiast do show up on those lists, when wine joins with connoisseur, it carries connotations of flavor, rather than just knowledge of vintages and terroir.
I was surprised by this one. For me buff, goes most readily with history and war. I picture an independent scholar type who likes to hear himself talk. While history buff is the most frequent pairing with buff, fitness buff, conjuring a different sort of image, has the highest MI. This is because fitness has a lower overall frequency in the corpus than history.
Animals figure prominently on the lover list (animal, cat, dog), connoting a real emotional connection between living beings. Nature also fits with this idea. But if this one is for lovers of animals, what's meat doing there? Meat enthusiast or connoisseur would imply some sort of knowledge base or heightened discriminatory abilities. Meat lover just implies pure physical or emotional enjoyment, much in the way that dog lover doesn't connote a knowledge of facts about dogs, just an emotional enjoyment of them.
Fanatic is for sports, but also, to a lesser extent, for a few other passions that one can get crazily caught up in. After buff, fitness has the closes connection with fanatic. A fitness buff knows a lot about keeping fit. A fitness fanatic takes it a little too far.
Fan may originally be a shortening of fanatic, but it carries less frantic or crazy energy and perhaps more of a sense of loyalty. The top three MI score spots go to teams with big followings. Sox probably benefits from the fact that two teams bear that name, though Red Sox fan is about three times more common than White Sox fan.
A obsessiveness step beyond fanatic is freak. But here the connotations tend toward the highly regimented kind with neatness, germ, control, and organization. Gadget, computer, and TV also have a obsessive, mechanical aspect to them. A fitness freak is maybe a bit too strict and controlled about their regimen.