Hi, John,
The credibility of the other party - I've frequently seen parties in a negotiation where someone tries to negotiate by starting with the absurd.
"How much would you like to pay?" (for a $15,000 watch)
"$1000"
End of discussion, the first offer is so absurd they have lost all credibility.
Of course, some would justify that with, "you don't ask, you don't get."
Another variation of this is my daughter just now rephrasing something we agreed upon in, in a previous heated discussion, in a way not at all what I thought we agreed.
"You agreed to let me use the xxxx we saved by not doing this, to let me do whatever I want."
What I agreed to was, "Ok, you can use the money we saved by not doing yyyyy for zzzzz" after she proposed that in the heated original discussion.
By mis-representing our previous agreement, reached after heated discussion, I am inclined to NOT confirm the previous "agreement."
Related to your example, people who tend to sweeping generalizations, "all Blancpains chronographs are high strung and unreliable" or "X is never true" (your example) or "TAG's are crap and only for aspiring newbies who know nothing about real watchmaking" already lose credibility points with me, as they seem to with you as well.
Thanks for your comments, and my best to your better half. I can easily understand how she feels, mine frequently feels the same way (maybe always... )
TM