Speaking with others can be quite a chore sometimes, regardless of the topic.
I don't feel qualified to label which are and which aren't "intelligent" as, really, I am quite dense myself. I shall therefore take the liberty of replacing the word "intelligent" with "stimulating" for reasons explained in my self-deprecating remark.
I do enjoy stimulating conversation, as I'm sure most do, but it can be quite hard to come by when no one seems to share your interests. I tend to become infatuated with things that aren't necessarily useful in any way, so the lack of interesting confabulation is really my own fault. These hobbies can, however, come in quite handy when someone asks a question about them , rare though these instances may be. At least,they would if anyone took me seriously. Being a young woman, I do not have to rely upon a mental illness to receive condescension from others. Between all of my shopping and boy-talk, how could I possibly have time for things like thinking? Why ask a person you so clearly think to be intellectually inferior anyway? This vexes me so.

I've had to read this comment about sixty times to ensure its coherency, a task much less easily performed during spoken dialogue. Yes, the give-and-take pattern is simple, but I've so many thoughts that wish to burst out all at once. Getting those rambunctious things to line up single-file can be quite difficult. At least in messages such as these, I am able to just type whatever pushes its way out first, then cut and paste and rearrange in whatever way is the least scatter-brained.
I've no idea if I've even answered your question. I've rambled on so much 'twould be a shame if I didn't.