Not only do the sales peole say "Yes", they promise to deliver it within xx
Re: 7: Promising before planning
In an email, Allan P. Clapp reminded me of one of my worst nightmares: the salesperson who says Yes to a customer before talking to the developers.
Not only do they say "Yes", they also promise a delivery date before even telling the development team about the "feature". If the developers say 2 months, the sales person or management says they have to have it in half or less time and schedule it accordingly. When it is not delivered "on time" but actually takes the time that the developers stated, the developers are blamed for delivering it "late".