I wish I had a nickel for every time a marketing director asked the elevator speech question: "What if someone asks, 'What do you do?' and you have 20 seconds to answer? What do you tell them before the doors open and one of you gets off?"
I think, therefore I am
Since professional service providers tend to spend a lot of time in their head, they're ready to pitch at the slightest glimmer of interest from another human being (prospect). The brain is the default filter for everything.
Lawyers, for example, might offer an elevator speech along the lines of "I add value to leading privately held companies by addressing the sophisticated legal issues relating to complex ownership succession."
Or, they might turn themselves upside down and inside out figuring out, as one expert recently put it, how to "spark interest in the potential client without sounding like a salesperson."
The question, however, is not about wanting a snappy summary of how you make a living. It's not about re-framing the question from the other person's point of view to come up with a non-pitch pitch.