I get the feeling often that I have something to do but can't remember what it was, but for talking and posting, it's usually that feeling of "I probably shouldn't have said that" more than "I think I have something to say but don't know what." My brain to fingers filter does not always work. Sounds like yours is working fine.
Pen, I think you need a "home thread". You'll feel much better. A lot of folks here have a thread or two that they always go back to. It's more like a lounge than a thread with a topic. You have your choices laid before you here in Office Party - Peace, Calm and Serenity, House of Love, This thread shall die...but not today, this thread shall never die (or whatever the hell it's called), the Whatever Thread. Obsessive Rep Point Checkers Club. In the Super-Secret-Mod-Proof room there's Mscelina's Fang Relief and SoccerMom's Playhouse too.
There's all varieties of serious and silly in each of them.
And if you like to run the course of humor - you have recovering rep addicts and the comedy cabaret in humor writing.
Find a home thread. then you'll almost always have something to say and sometimes you might even say more than you should. And sometimes you'll say things you probably shouldn't.