I have Venus and Mercury in Gemini, and in the last relationship we had Mercury opposition Mercury. This guys communication really annoyed me - I felt like he didn't listen at all, he kept coming up with ideas he had no grounds for and wouldn't follow up on them. Unbearable. But then also, my Saturn was in his third house, so my more intellectual proficiency had a negative reinforcing effect on him.
It did make me feel intellectually disconnected which is a huge no-no for me.
However, there were other really bad aspects between us in the composite which is why it didn't work out.
Even more unbearable for me was my other ex, with Mercury in Cancer, who would seethe in silence and would not talk to me at all. Now that's torture for a Gemini Venus/Mercury!