While looking into an answer for "Sick and tied" and "sick and tired", I stumbled across the idiom fit to be tied which according to thefreedictionary means angry and agitated. (As if needing to be restrained.)
A second search turned up that this refers to the practice of bounding uncontrollable, dangerous people into strait-jackets. How did we make the leap from crazy and uncontrollable to the general usage today of ticked off? Or is my understanding of general usage today incorrect? Is it common for these phrases to become so watered-down over time?