get on like a house on fire

joined at the hip

two peas in a pod

be a good laugh

fair weather friend

bury the hatchet

through thick and thin

hit it off

clear the air

be on the same page

birds of a feather

turn your back on

put (something) down to

be drawn to (something or someone)

turn sour

let (someone) down

take to (something/someone)

let (someone) down

look down on

drift apart

stand up for - your convictions; someone

have/got someone's back

catch up with (someone)

hold (someone) back from

iron out

settle down

let (something) build up

stand up for

take an instant (dis)liking to (someone or something)

keep in touch vs get in touch

come to terms with

keep to yourself vs keep something to yourself

get on (someones) nerves

put a strain on

have a falling out with someone (phV: fall out with someone)