My limit was that after a decade of single-handedly spec'ing, programming, supporting and otherwise being in charge of all internal app development efforts for the $6 billion North-American arm of a $50 billion multinational corp... I still wasn't deemed worthy of the opportunity of a green card, or a salary commensurate with my responsibility and impact on the corp. The day I got my GC by other means and thus was no longer stuck working for them, I gave my 2 weeks, to everyone's surprise and disappointment! And that was with no jobs lined up after that.