Many women wind up associating lubricants with internal exams, which are decidedly nonerotic experiences. Beyond that, in my opinion, K-Y is probably the worst lube. It's gloppy and it smells medicinal. We like Probe. They consider lubricants unnatural.
Some lovers consider lubricants messy.
Then there's the objection that lubricants taste bad, which interferes with oral sex. Different lubes do, indeed, taste different. Winks and Semans suggest making an evening of taste-testing several brands. Other lovers view lubes as an interruption. Far from being an interruption, that moment of erotic anticipation can get you even hotter.