The other problem I see is that all the "solutions" are behavioral. OK: let's say the T is fantastic at this sort of intervention and manages to shift the client out of the complaining behavior. Everyone cheers. But if the complaining is a defense, and it probably is in a high majority of cases, a new defense will simply arise to take over the job. The underlying issues have not been addressed--only the outward manifestation that happens to annoy everyone.