if you say so

a polite way of saying no
girl1: omg!! isnt jason so hott?!?!!

girl2: if you say so…
phrase that can indicate continued concern in response to attempts at alleviation.

can also be used to politely disagree or imply that someone is lying.
person a: i’m fine.
person b: if you say so…
a very polite way of calling someone a liar after they tell you something that you know is utter bullsh-t.
man #1: i saw elvis at the 711 this afternoon.

man #2: yeah, tell me another one.

man #1: no, i really did see elvis.

man #2: if you say so.
if you’re annoyed or angry with whoever you’re talking to it basically means whatever, just get the h-ll out of your face, shuttup, and leave you the f-ck alone.
if you’re not mad it means: ok, sure i’ll go along with that; or i’ll do it later.
can also be used with affection to a loved family member in place of “i love you too,” in some cases.
ex. 1
teen: (goes downstairs to get a snack and drink)
grandmother: (limps in with cane) it’s your day to clean the kitchen
teen: (in an indifferent tone) if you say so (goes upstairs with snack and drink and continues to play on computer)
teen: (thinking to self) i can’t stand that b-tch, she gets on my f-ckin’ nerves! she needs to turn on the d-mn air conditioning cuz it feels like a sauna up in dis b-tch!
grandmother: (downstairs in kitchen)(limping slowly with cane to get a drink)

ex. 2
(daughter and father finishing a phone conversation)
daughter: what are we doing when you get off work?
father: i don’t know sweetheart, probably nothing (obviously kidding). i have to go now, i have a customer that i need to get back to. i love you.
daughter: daad come on!
father: i have to go now, i’ll call you back later. bye, i love you, and i’ll see you when i get home.
daughter: if you say so, bye! (hangs up phone and continues to watch tv)