Because life and business do not have clear delineations. The rule at my company became never use these communication tools at work: except work for investment

Because life and business do not have clear delineations. The rule at my company became never use these communication tools at work: except work for investment bankers is 100 hours a week, except your friends and coworkers become the same people, except business is everywhere, so it's impossible to have a conversation that isn't at least business related when everyone you know wants to talk about the stock market.