Can agile methodology be applied to all software development projects?

I’ve been involved with software development for many years and very rarely have I ever seen “agile” process methodology work out. Could this be because of the nature of the software development projects I tend to specialize in or is it just that none of the product teams I have worked with understood agile methodology properly? In other words, are there some software projects where agile methodology will never work due to the very nature of what the software is?