The last drop makes the cup run over.

This is a variant on "The last straw breaks the camel's back" and reminds us that everyone has a breaking point. Some people boil over at the least irritant and some patiently put up with hassle upon hassle but eventually they too will snap. Recognising a looming problem before it actually occurs is a good life skill - a wise person will take action before the storm breaks. If you are on the receiving end, giving some kind of signal that you are being put upon and that you are likely to do something about it will alert a sensible manager or spouse etc. who might then change their ways. If you are the source of someone's irritation consider heading off trouble by thinking ahead and mending your ways before the last drop makes the cup run over.


If your PC's near its last drop:
http://www.clarkscript.com/task-manager.html