つい

Accidentally, Unconsciously, Against one's better judgement

つい楽らくな方ほうに流ながされてしまう。

I always end up unconsciously taking the easy route.

Explanation

「つい」 means 'before I knew it', 'without meaning to'. You knew you shouldn't, or never planned to, but weak will, habit, tiredness or temptation made you do it in a careless moment. It is almost always followed by 「〜てしまった」, with regret: 「ダイエット中なのに、ついケーキを食べてしまった」 (I'm on a diet, but I ate the cake anyway).

Mixed up with

「つい」: weak will, giving in to temptation (ate it though I shouldn't).

「うっかり」: carelessness, not paying attention (forgot my keys, missed my stop).

「つい」 before a time word means 'just a moment ago': 「ついさっき」 (just now), 「つい最近」 (just recently).

Examples

先生せんせいに怒おこられると、つい笑わらっちゃうんだよね。
When I am being scolded by the teacher, I unconsciously laugh.
電車でんしゃが遅おくれると、ついイライラしてしまう。
When the train is late, I can't help getting irritated.
ごめんタケシ君くんのクッキーが目めの前まえにあったからつい食たべてしまった。
Sorry Takeshi-kun, your cookie was right in front of me, so I absentmindedly ate it.
運転中うんてんちゅうに携帯けいたいを使つかったらだめなのは分わかっているんだけど、メールが来くるとつい携帯けいたいを見みちゃう。
I know that I shouldn't use my phone while driving, but when I get a text I unconsciously look at my phone.
運転うんてん中ちゅう、ついよそ見みをしてしまう。
I sometimes accidentally look away while driving.
運動うんどうを始はじめると、ついやり過すぎてしまう。
When I start doing exercises, I always end up accidentally overdoing it.
笑わらってはいけないのに、つい笑わらってしまう。
I know I mustn't laugh, but I can't help laughing.
「つい食たべ過すぎてしまう」なんて言いい訳わけだ。
Saying things like: 'I unconsciously eat too much' is just an excuse.
１００円えんショップに行いくとつい買かい過すぎてしまいます。
I always accidentally buy too much when I go to 100 yen stores.
ダイエット中ちゅうなのに、ついアイスクリームを食たべてしまう。
Against my better judgment, I eat ice cream while on a diet.
そんなにおもしろくない番組ばんぐみでもつい見みてしまいます。
Against my better judgment, I end up watching TV programs that aren't even that interesting.
思おもい通どおりにいかないとついイライラしてしまう。
Against my better judgment, I always get irritated when something doesn't go as I imagined.
赤あかちゃんを見みるとつい頬ほおが緩ゆるんでしまう。
I can't keep myself from unconsciously smiling whenever I see babies.
失敗しっぱいした時とき、つい人ひとのせいにしたくなる。
Against my better judgment, I find myself wanting to blame someone else when I make a mistake.
仕事しごと中ちゅうでもついスマホをいじってしまう。
I always find myself unconsciously fiddling with my smartphone while I am working.
お腹なかが空すいていなくても、目めの前まえに食たべ物ものがあるとつい食たべてしまう。
Even when I'm not hungry, if there's food in front of me I end up eating it.