I know a guy who always struggles with chemistry with women.
He doesn't do things exactly quite right. He uses all the right tactics and techniques with women, but he uses them in this way that is just a little bit 'off'.
When you try to point it out to him, he insists that in fact he is doing everything correctly. Then he says it must be a problem with the technique or that the technique doesn't work for him.
Regardless the reason, he constantly runs into issues where he has what he thinks is a great date, followed by the woman telling him at the end of it (or texting him later on) that she "just isn't feeling it."
"There's no chemistry," she says. Or "I didn't feel a spark."
I can't get him to fix the vibe/calibration issues. He doesn't see these as a real problem, probably because he's unable to pick up on this issue himself, even when women point it out or coaches point it out.
However, I wanted to help him, so gave him a tool I knew he could use: a 3% frame to help push things his way in those edge cases where it could go either way, but "I'm not feeling a spark" is the deciding factor.