I don't usually talk a lot. But when certain subjects come up, I can't stop babbling. I try my best to be polite and not monopolize the conversation....but sometimes it is difficult.
1. My daughter - She does a LOT of things. A LOT. So I frequently have a lot to say about things she's accomplished or what she is currently doing or what she has planned. Sometimes it's a little too much.
2. Sailor Moon - I love Sailor Moon a little too much.
3. Bad writing in books - I review a lot of books. Most of the time, the book is already for sale to the general public by the time I read it. I honestly have lost count of the number of books that are grammatically incorrect, have numerous misspellings, and are just plain difficult to read due to the errors. If you are going to write a book, do it right. Get some good editors and have multiple people read through your manuscript. Don't just toss it up on Amazon because you said it's finished.
I think those three are the main culprits. Sometimes, if I find a new Thing that I think is super interesting, I'll do a ton of research on the subject and babble about it to my friends. I try really hard to not do that. I know it can be annoying.