For what it's worth, I really don't like the culture of "challenging" that is rampant in the Church. I just don't like the attitude it presents. For example, it's NOT "Moroni's challenge". That word isn't there. It's "exhort" and "invite" - not "challenge".
So, I personally don't "challenge" people very often. Rather, I extend an invitation - since that removes all of the "machismo" associated with a "challenge" - and since invitations can get turned down all the time when they simply aren't appropriate without any need to "save face" in some way. Appropriate invitations, on the other hand, are seen as a wonderful gesture - even in those times when they still can't be accepted due to reasonable conflicts.
35 minutes ago