Excessive overtime. While some companies plan for overtime, and include it as a process requirement (one blatant example was EA as documented by EA_Spouse and subsequent lawsuits). Generally, crunch mode and overtime are strong indicators of poor planning and resource mismanagement. While some overtime could rescue a project marginally behind, long term overtime is the sign of a death march and can be the result of several things, most of which are mismanagement.

I strongly recommend reading the book Death March. It is a reasonably light read, but gives examples of the 4 types of death marches. Sometimes you don't mind, and indeed would willingly "sign up" for a "glorious failure" while others are going to be miserable. The term "sign up" came from The Soul of a New Machine, which was a hardware death march.

Much of our problems with time and effort estimation are due to poor skills at estimation. This is further compounded by the attitude of many management track personnel that "everything is negotiable."