Tell them upfront, “Sure, I’ll go, just don’t be mad at me if it doesn’t work out, or there’s no chemistry.” Be open to the possibility that you might have a genuinely good time, but don’t hesitate to let whoever’s setting you up know that you’re doing it for fun, and to get out of the house, and that you are going into it with the idea that whatever happens, happens. Try to enjoy the conversation and see where it leads. You never know when a casual introduction might turn into a connection.