You can literally work on software for any industry, company or government in the world. I would think you would have some sort of preference. At the least you should be interested enough in the place your are interviewing at to find out what they do and and then tell them you are interested in working on that. Otherwise you just come off as a mercenary or desperate.
The thing is some people really don't care what they work on. As long as the pay is good and they are getting to program(or whatever other task they enjoy doing), the actual application doesn't matter.
