I worked for Advanced Network and Services, which operated the NSFNET and was later acquired by America Online. Then one day the company was acquired by WorldCom. A few years later the CEO was sentenced to 25 years in prison for a ~$10 billion fraud. As a systems administrator I knew nothing about any of that, but I could tell that the new management included a lot of players and empire builders. That's the signal that told me to quit a few months after the acquisition. Employees were invited to invest their retirement savings in a mutual fund that contained only WorldCom stock. Many of them lost everything. Pay attention to those signals.