The idiom the straw that broke the camel's back is from an Arabic proverb about how a camel wearing shoes is loaded beyond its capacity to move or stand.
This also gives rise to the phrase "the last/final straw", used when something is deemed to be the last in a line of unacceptable occurrences. Every notice how most of the times in a relationship it's something small(which leads to a big fight) that winds up ending it?
Most relationships have disagreements that the beauty of it but after a while the failure sets in when one too many compromises or one too many disagreements reaches a point when disgust sets in.
Relationships are not just confined to lovers, even in familiy or even friends there things happens, while the yarn and tale about trying to repair it and wise words "remember why we started this in the first place" all comes to mind, it does not hide the fact disgust sets in and leaves an ugly taste in your mouth
I had no problem digging in and battling through some very hard times, but something small made me say "enough is enough". The revelation hit, not over a major difference, but rather over something quite trivial.
The last straw is usually based on disgust its an emotion that will engulf your mind body and soul... its not a bad thing. It can come in handy to use it to get rid of poisonous people as well.