Descriptions
not a very reliable friend
a fair weather friend
suspicious
something fishy
To be really happy
To be on cloud nine
very expensive
it cost me an arm and a leg
to be furious
blow one´s top
informal chat
shooting the breeze
bragging about oneself
a bag of chips
imagine different ideas
let your mind wander
being stuck on a problem
being washed up
to remind something to someone
jog somebody´s memory