You’re taking the talk about lunches too literally. “Let’s have lunch sometime” often means something more like “let’s pretend that we like each other enough to eat lunch together, without actually doing it.” As long as the lunch is hypothetical and in the indefinite future, it’s easy to agree to. When you try to pin down a time and place, the other person finds silence easier than scheduling a lunch that he doesn’t really want, or explaining that he never intended to have lunch with you anyway. Let it go.
You’re taking the talk about lunches too literally. “Let’s have lunch sometime” often means something more like “let’s pretend that we like each other enough to eat lunch together, without actually doing it.” As long as the lunch is hypothetical and in the indefinite future, it’s easy to agree to. When you try to pin down a time and place, the other person finds silence easier than scheduling a lunch that he doesn’t really want, or explaining that he never intended to have lunch with you anyway. Let it go.