I have noticed this in many mathematicians: they will start explaining you something that you are completely unable to grasp, being completely ignorant of the specifics of the field. However they will insist in their pursuit and the polite thing to do is to try to understand some general idea as best as you can, and they don't really expect you to understand everything that they are telling you. This has happened to me various times, first time I was not even an undergrad yet.
Mathematicians know mathematics is hard, and hardly ever expect you to fully understand they're saying, as you cannot compact in a handful of sentences something that took you hours, days or weeks to fully grasp. It doesn't mean that it's a waste of time: in an otherwise incomprehensible monologue you might find a nugget of knowledge that will stay with you, and will form a foundation on which the future understanding will rest.
I feel the same way. I'm an engineer not a mathematician but I've always thought if I can't sit down and explain the problem I'm working on in a way that makes sense to a layperson then I don't understand the problem well enough It can be a useful way to quantify your own knowledge as well.
Conversation would be so much more lively if the general population knew the basic results and definitions of maths. :p
I'd wax poetic about most reals being uncomputable, but good luck explaining cantor's diagonal theorem, measure theory, why we need measure theory, what a real number is, why we need real numbers, how sqrt(2) isn't rational, how numbers can be transcendental, what a limit is.
There is so much background needed for maths. People feel like they don't have the talent to get it, whereas really it's a matter of putting in the time to get comfortable with the basics.
