I know it is bad if a woman betrays you, but if she wears little boob-tubes like that, you forgive her, don't you?
Of course you do - and if you're Bond, you can kill her afterwards for revenge.
But back to the topic, the single most horrifying moment in the series must be Blofeld in drag in DAF. To see a character go from an eerie and sinister villain in the shadows in FRWL and TB to that was truly disgraceful. As was the film itself, but that's a whole other story. Jaws' romance in MR is pretty bad too, as is how he suddenly went from unstoppable henchman to sappy idiot.
There are some others too - the ending of FYEO was too much and too topical; it may have been funny back in 1981, but now it's embarrassing. And then Moore literally became a clown in Octopussy, but at least that contributed to the plot, unlike most of the other weaker moments in the series.