If people are up in arms, they are complaining or protesting angrily about something.

If someone can dish it out but can't take it, they criticise people freely but dislike being criticised.

Rivers of indicates a large amount of moving liquid, like rivers of sweat running down someone's brow. It can be figurative like saying that rivers of blood will flow to indicate serious conflict.

It something doesn't amount to a hill of beans, it is worthless. 

If you catch someone on the hop, you do something when they are not expecting it and are not ready.

If something is the height of folly, it is completely ridiculous and will end up badly.

If you are in the grip of something, you are beingcontrolled by something unpleasant or that you don't want to be controlled by.

If you are in the grip of something, you are beingcontrolled by something unpleasant or that you don't want to be controlled by.

If you get a grip on yourself, you control your emotions and feelings under difficult circumstances.

If you loosen your grip on something, you hold it or control it less tightly.