Although I could argue there are worse scenes in general, the one with the most impact for me, that almost cut my Trek fandom short... the handholding jellyfish at the end of TNG's debut 2 parter.
I watched it when it first aired, and I cringed so hard that my family thought I had a stroke. Really, those episodes were full of stuff that made you feel like an ass telling your friend new to Trek that "it gets better," but that really was the whipped cream and cherry on top.