Is Keith Olbermann, MSNBC's top-rated anchor, on the verge of yet another professional meltdown? His feuding with "Hardball" host Chris Matthews is nothing new. But now we're told notoriously odd Olbermann is lashing out at the rest of his network's talking heads. During West Virginia primary coverage the other night, Olbermann began pounding the table when lead White House reporter David Gregory didn't wrap his segment quickly enough to satisfy him. Olbermann recently encouraged management to oust the cable channel's lone conservative, Tucker Carlson, and it's also no secret among producers that Olbermann refuses to introduce Dan Abrams' show, which follows his own. Olbermann walked out of MSNBC years ago in a huff after also blowing up at ESPN, so TV insiders are curious if this recent behavior is a sign that history will repeat itself. MSNBC did not respond to our calls and e-mails seeking comment.