First, a thesis is supposed to demonstrate that you can take a project and bring it to a genuine conclusion. Pick a topic that will help you professionally. Employers will sometimes ask about your thesis or even want to see it – especially if you go into some branch of education. Your choice of thesis can help you get a job or hold one.
Pick a topic that you are happy to talk about at a cocktail party. People will often ask you, in making conversation, “What is your thesis about?” A good test of your wisdom in picking a topic is the amount of pleasure you get in answering. Here’s why: A thesis project involves some frustrating times; your personal interest in your topic is your best help in getting through that frustration.
A thesis should be useful. You’ll be happier about doing a thesis if you feel that somebody will use it. And you’ll want to do a better job if you feel that somebody will read and use your thesis. It is even better if the thesis is useful not just at the moment of completion, but also later.
It should not be a snapshot of information that immediately becomes dated; the thesis should ideally be something with information you can talk about and that people can use for years. If you are going into any branch of education, try to make your thesis something that can become a journal article; such articles look very good on resumes.