The actor is yet to sign up to Iron Man 4, prompting rumours that he may be quitting the film franchise.
For example, nurses may be quitting Malawi because their salaries are not being paid or because hospitals are crumbling; entrepreneurs may be moving abroad because the business climate back home is wretched.
In turning his back on the revolution in thinking that brought New Labour to power in 1997 that even though few Britons were very rich, many aspired to be Mr Brown may be quitting the hard-won centre ground too soon.
But columbines are short-lived, and yours may simply be quitting.
Webb did, however, suggest that he may not be quitting presidential politics, hinting at a possible independent bid.
I want them to know that when adventure comes knocking, the most sensible thing to do may be to quit a perfectly good job.
If your channel is starting to dangerously fall apart, your only option may be to quit.
This may be because quitting perfectly good jobs is something of a family tradition.
A simple illustration would be that person A might smoke to help manage their stress and want to quit as a result of social pressures, whilst person B might enjoy the social aspect of smoking but may be looking to quit due to health concerns.
"A patient who asks a clinician about using the e-cigarette for quitting smoking may be signaling readiness to quit smoking," they wrote in a May 2014 clinicians' brief.
