I love love love a quick wit and the ability to banter. In my mind, if both of you have that quality then you'll never have to worry about "not having anything to talk about" beyond "how was your day" stuff. You can feed off each other forever and make each other funnier in the process.
This times a million. That's probably the thing I love most about the relationship I'm in. My girlfriend and I have mastered the hidden art of trash talking. She's so quick on her feet with banter, jokes, and stupid puns, and I'm the same way. She loves it when I give her shit as well, and I love it when she does it to me. It never gets old. We'll be laying in bed about to sleep and she'll be trying to fix the covers with her fucking feet and she'll get the comforter all halfway off the bed and make a right mess of everything. At this time she knows she better fix it fast before I speak up about it, but too late. I'll just turn my head and look at the situation and say something like "oh my god there's no way you're 19 years old and you can't figure out a fucking blanket" and then she won't stop laughing for a minute and I'll help her fix it. Then later when I go to the refrigerator to grab the pizza box and I pull it out without realizing that the carton of eggs was sitting on top of the pizza box and I break half of the entire carton on the floor, I'll just look up at her with self-disappointment in my eyes and she'll say "jesus christ did your parents literally never teach you how to handle eggs?" and then I'll try and spin the banter back at her between laughs and she'll help me clean up. I love it so much. I was raised as an older brother of two sisters and so I have extensive experience making little quips. Someone has to hear them and I'm glad she genuinely loves it. There's never a dull moment in the relationship.
I've always thrown banter at my girlfriends but all the ones in the past either just laughed or took it seriously. I can't do with that. I can't be the boyfriend who never says a mean word. I've never been that sort of sibling, friend, or lover.