Earlier today, Microsoft released a letter from CEO Steve Ballmer to the Yahoo Board of Directors.
In the letter, Ballmer recounts events of the last few months and goes on to say that if good faith negotiations don't begin soon, and a deal is not concluded in 3 weeks, Microsoft will "be compelled to take our case directly to your shareholders, including the initiation of a proxy contest to elect an alternative slate of directors for the Yahoo! board".
The letter which starts off subtle then turns somewhat hostile (as in 'hostile takeover bid') lays out Microsoft's position clear as day.
As they used to say in the movies, "We're comin' for you". Play nice or else.