Fancy dress costume parties are fun events that appeal to individuals of all ages. They are enormously fun because there is so much about fancy dress costumes. It is a treat to the imagination. You have to wonder what to go as. When you finally decide, there is the costume to design or hunt through the costume shops for. You also spend all the days following up to the party scanning every random thing around you to see if it would make a great prop to go with your fancy dress. And then at the party itself, there is the excitement at seeing all the other costumes, and how your friends flesh out the character they are playing for the evening event. Of course, you are playing some character yourself and it probably tickles you silly.

But fancy dress costumes are not only trotted out of the closet for costume parties. They are used in movies, and the ones used in movies are very realistic and are accompanied with a lot of makeup and body gear to make an actor look like whatever monster/ alien/ mutant it is that he is supposed to represent in the film. Getting one's hands on these costumes can garner a lot of attention and appreciation from other film aficionados. But it is not at all easy to pick up an original costume that has been used in a film that has been released to the public. Especially famous movies that have become iconic hits like Star Wars, Star Trek, Planet of the Apes, etc. Original costumes from these films become collectors' items that are auctioned off for hundreds or even thousands of dollars.

Plus of course, movies made on that scale become a syndicate of merchandising costumes, toys, mugs, etc off in lieu of marketing for their eagerly waiting consumers and movie viewers and fans.
Fancy dress costumes are also used as a fashion statement by several individuals who believe that every day is being about exactly who or what you want to be. It is an individualistic freedom sort of mantra about living it up and empowering yourself. Depending on which costume they are wearing for a particular day or period in their lives, they try and live up to its persona. But this is not always a healthy sort of practice because it means that the person who believes in living this kind of lifestyle is indulging himself or herself in escapism, that is, they cannot face the reality of being just themselves in their own lives. In this case, fancy dress costumes just become an emotional crutch and can have lead to or stem from psychological problems with adjustment and adapting.

Some people also make a profession out of wearing fancy dresses. These are professional impersonators. They attend events, parties, populate Las Vegas and literally learn up everything about the famous person or celebrity they are replicating. They see it as 'acting' but often end up absorbing certain parts of their impersonation into their own lives. Nonetheless it's a fun career with a lot of excitement and change.  Michael S. Jones