One of the pleasures of having a research activity is that you get to visit research institutions and ask people what they do. Typically, the answer is "I work in X" or "I work in the application of X to Y," as in (made-up example among countless ones, there are many Xs and many Ys): I work in model checking for distributed systems. Notice the "in."
This is, in my experience, the dominant style of answers to such a question. I find it disturbing. It is about research as a job, not research as research.
Research is indeed, for most researchers, a job. It was not always like that: up to the time when research took on its modern form, in the 18th and early 19th centuries, researchers were people employed at something else, or fortunate enough not to need employment, who spent some of their time looking into open problems of science. Now research is something that almost all its practitioners do for a living.
But a real researcher does not just follow the flow, working "in" a certain fashionable area or at the confluence of two fashionable areas. A real researcher attempts to solve open problems.
This is the kind of answer I would expect: I am trying to find a way to do A, which no one has been able to do yet; or to find a better way to do B, because the current ways are deficient; or to solve the C conjecture as posed by M; or to find out why phenomenon D is happening; or to build a tool that will address need E.
A researcher does not work "in" an area but "on" a question.
This observation also defines what it means for research to be successful. If you are just working "in" an area, the only criteria are bureaucratic: paper accepted, grant obtained. They cover the means, not the end. If you view research as problem solving, success is clearly and objectively testable: you solved the problem you set out to solve, or not. Maybe that is the reason we are uneasy with this view: it prevents us from taking cover behind artificial and deceptive proxies for success.
Research is about solving problems. At least about trying to solve a problem, or -- more realistically and modestly -- bringing your own little incremental contribution to the ongoing quest for a solution. We know our limits. But if you are a researcher and do not naturally describe your work in terms of the open problems you are trying to close, you might wonder whether you are tough enough on yourself.