"it's raining cats and dogs"
It's raining very hard.
"get cold feet"
decide not to do something
"under the weather"
to feel ill
"piece of cake"
easy
"just for kicks"
just for fun
"butterflies in my stomach"
feeling nervous
"head over heels"
very happy
"let your hair down"
relax
"not my cup of tea"
not what I would choose
"stay on track"
focus/stay on topic
"monkey around"
to play or waste time
"give me a hand"
help me
"get on my nerves"
annoy
"don't cry over spilled milk"
don't complain about something that's already happened
"in hot water"
in trouble
"in the dog house"
in trouble
"pulling my leg"
teasing you
"barrel of laughs"
funny
"spill the beans"
tell a secret
"crack me up"
make me laugh
"let the cat out of the bag"
to tell a secret
"get off on the wrong foot"
bad beginning
"hot under the collar"
mad
"apple of my eye"
the one I like best
"on the right track"
doing things correctly