Been there! My boyfriend has an overdeveloped brain so he tends to overthink things or explain things in intricate detail. I love him and its not like this 24/7, but it can be trying sometimes.
Several times on a long ride to somewhere (quilt shop, his place, date destination) he'll go on about something that will go completely over my head. Like the mathematics of Dungeons and Dragons (yes I have to be dating a total nerd who is too smart for his own good). He went on about that one for a good half hour and I just about fell asleep. And at the end I have said "You lost me". Really I mean "I don't get it so shut up", but I don't want to hurt his feelings. Instead of taking the hint that my average brain is not going to get it he'll go over it AGAIN and explain it in even greater detail. After like the fourth or fifth time I had to politely tell him that I love him, but he makes my brain feel stupid going on about something I don't get and that I didn't say anything before because I didn't want to hurt his feelings.