Science shows that self-discipline taxes the soul
iijiij.com
iijiij.com
http://danariely.com/2012/08/15/understanding-ego-depletion/
I made a separate submission for the above link, it deserves it.
The mental resource that is being impacted by such things as exercising self-control seems to go far beyond anything we typically define as 'ego' as in self-image and I think the implications are therefore even more wide-ranging than ego-depletion, although he does seem to imply that he appreciates this.
I haven't updated Chrome in the last 3 days - and now I wont :-D (MacBook Air late 2010, Snow Leopard)