something's gotta give

something's gotta give
It's "Something has got to give." Or in informal talk "Something's gotta give."
Meaning that you have opposing forces at work, pushing against each other.
The situation is not stable. One of the two forces that is pushing is going to overwhelm the other. Someone will win. For example, if two people are arguing and both are refusing to change their argument, for them to reach an agreement, something would have to "give" (i.e. one or both of them would have to "shift" their position)