Constantly changing focus and reorganization, lots of wasted effort and money on aborted initiatives, lots of corporate "speak" without real change/action/commitment.
Most critically ---- and what lead to my ultimate departure ---- a corporate re-org left me with a new manager who was determined to eliminate me and other team members. Despite a year of best efforts to improve the situation (along with futile efforts to enlist help from HR), leaving Amgen was the only option.
Some people seem to thrive at Amgen. Most coworker friends I know personally have lots of negative experiences at Amgen and ultimately have left because of seasonal corporate restructuring or other impedances to growth and advancement.
Leaving Amgen was the best decision I ever made and on the other side has been tremendous growth, opportunity, and fulfillment -- in terms of career, finances, and quality of life.