rubicons

"A limit that when passed or exceeded permits of no return and typically results in irrevocable commitment."

OR

a river in north central Italy. Julius Caesar crossed it and a war began.

and here is something a friend wrote me that got me thinking about rubicons: "As for being careful what I wish for....I crossed on the river there'll be no returning I crossed all the bridges and I watched them all burning and now I'm a stranger to a strange land I'm driven where all is forgotten but nothing's forgiven"