I believe all are familiar with the following phrases. For newcomers, they can be confusing and for long term expats just frustrating. This is not meant to be a serious topic, just a little fun.

แล้วแต่คุณ (up to you) - A double edge sword

Me: Where would you like to go for valentines day dinner?

Her: แล้วแต่คุณ

Me: Ok, McDonalds should be ok.

Her: <silence - for the next 3 days>

ไม่เป็นไร (It doesn't matter, never mind, forget it)

Me: I can't afford that and besides it's ugly

Her: ไม่เป็นไร <meaning - she plans on a headache tonight or more>

เกรงใจ (considerate of feelings)

Me: Why didn't you wake me for my important meeting?

Her: เกรงใจ

The latter could also mean she was too afraid.

Totally agree on on "up to you"

But if you get it wrong, there is a price to pay

Up to you actually translates to "this is a test, choose wisely"

Wait for you Long time na

I answer all requests for new handbags/shoes/dresses etc. with "mai mee dtang". That seems to translate easily but is rarely appreciated or understood. She then starts talking about something sticky.......it's a confusing language.

I hear very often " แล้วแต่ " instead of " แล้วแต่คุณ " : thai people like short sentences

I hear very often " แล้วแต่ " instead of " แล้วแต่คุณ " : thai people like short sentences

Actually that is also what I use most often and suspect it may be more common than the full formal one.