Do Not Desert Me, Oh My Darlin!

Why are so many F/SF movies set in a desert, or have significant portions in deserts? _Them_. _Tarantula_. _Monolith Monsters_. _Forbidden Planet_. _Star Wars_. _Dune_, obviously. The _Tremors_ movies and TV show. Even the early parts of _Iron Man_. On and on.

Now, in some cases the desert locale is necessary for the plot. Whatever's going on may need a dry environment for some reason, or needs isolation to get started good before people notice. The first origin of Iron Man was set in Vietnam, that decade's foreign war. It makes sense for the new one to be set where the current war is happening.

I suspect that in most cases the people making the movie simply wanted the emotional atmosphere of a desert area.