I often come up discussing (peacefully!) with people on a wide spectrum of topics, and equally often I have to debunk flawed arguments, in logic sense (see for example this question).
However I can't just come out with "your argument is not valid in pure logical sense!", because people I usually come up arguing with would just not understand, or worse just call me a weirdo (sigh)
Thus, how should I behave in those cases? Have you any suggestions, or meaningful experiences?