N3 Grammar: The Difference Between ~まま and ~っぱなし

N3 JAPANESE GRAMMAR
THE DIFFERENCE BETWEEN ~まま AND ~っぱなし

1. THE STRUCTURE まま: LEAVE AS IT IS…
Expresses: a state remaining unchanged, continuing exactly as before.
Grammar structure: Vた/ Vない/Nの ＋ まま

Also:
このまま: leave it just like this
そのまま: leave it just like that
あのまま: leave it just like that (over there)

Examples:
この野菜は生のままで食べておいしいですよ。
(These vegetables taste best eaten raw.)

山田さんの彼女は金を借りたまま、一向に返してくれない。
(Mr Yamada's girlfriend keeps borrowing money; at this rate she'll never be able to pay you back.)

このまま秋くんと幸せになりたいです。
(I want to stay this happy with Aki-kun forever.)

2. THE STRUCTURE っぱなし: LEFT AS IT IS..
Expresses: something that should have been done but was left undone. This pattern usually carries the speaker's criticism or dissatisfaction.

Grammar structure: V(drop ます) ＋ っぱなし

Examples:
さっきからずっと立ちっぱなしだけど、座らなくて大丈夫？
(Why have you been standing all this time? Can't you sit down for a bit?)

ドアを開けっぱなしにしないでください。
(Please don't leave the door open like that!)

妻がテレビをつけっぱなしで寝てしまった。
(My wife fell asleep with the TV left on.)

THE DIFFERENCE BETWEEN THE TWO N3 STRUCTURES ~ まま AND ~っぱなし
It's easy to see that although both structures express an unchanged state and a prolonged action, they are used differently depending on the situation:

~まま is used to emphasise describing a state, or in some cases a deliberate action by the speaker.

Example:
田中は魚を買ったまま食べている。
(Tanaka often buys fish and eats it as it is.)

~っぱなし, in many cases, describes an action with dissatisfaction or unwillingness, or to complain.

Example:
水を出しっぱなしにしないでください。
(Please don't leave the water running like that!)

See also:
Soumatome N3 Grammar Collection
50 Common N3 Japanese Grammar Structures