a bone of contention	a sensitive issue that causes argument
go round in circles	argue about sth repeatedly without finding a solution
in a nutshell	in few words
fight a losing battle	struggle against sth with no hope ofsuccess
rack one's brains	think hard about sth in order to find a solution
put our/your heads together	discuss sth especially to solve a problem
start the ball rolling	start a conversation/activity
put one's thinking cap on	start thinking about sth especially problem
the bare bones	the most important parts of sth
rock the boat	ruin a good relation
talk shop	discuss work matters when not at work
get on one's nerves	annoy sb
pass the buck	transfer responsibility to someone else
not mince one's words	speak frankly
get a grip	take control of sth/spmeone
throw sb off balance	confuse sb
hold one's tongue	keep silent
drive home	make sb fully aware
clear the air	relieve tension between people by saying sth
ring hollow	sound false