ばよかったWish one had or had not
Use ばよかった to regret a past choice: you wish you had done something, or wish you had not done it.
Looking back at a better alternative
This pattern compares what actually happened with a better possibility that is now unavailable. An affirmative conditional points to an action you failed to take; a negative conditional points to an action you did take and now regret.
The two directions of regret
An emotional afterthought
旅行中ずっと雨だった。傘を持ってくればよかったのに。
It rained throughout the trip. I really wish I'd brought an umbrella.
AnalyzeHere the ending strengthens the speaker's lingering self-directed regret. If said about another person's action, the same ending can sound reproachful, like blaming them for what they failed to do.
Regret, relief, and advice
ばよかった looks back at an unrealized better choice. In contrast, てよかった expresses relief or satisfaction that something actually happened. Also distinguish the target from ばいい, which normally gives present or future advice rather than expressing regret.
More examples
駅まで一時間も迷った。最初に道を聞けばよかった。
I wandered around for an hour trying to reach the station. I wish I had asked for directions at the start.
Analyzeホテルが満室だった。予約しておけばよかった。
The hotel was fully booked. I wish I had made a reservation.
Analyze旅行が終わってから、もっと写真を撮ればよかったと思った。
After the trip ended, I thought I should have taken more photos.
Analyze昨夜は遅くまで眠れなかった。夜にコーヒーを飲まなければよかった。
I couldn't fall asleep until late last night. I wish I hadn't drunk coffee in the evening.
Analyzeよく考えずに返事をしてしまった。すぐに答えなければよかった。
I replied without thinking carefully. I wish I hadn't answered immediately.
Analyze試験では大事な点を思い出せなかった。先生の説明をメモしておけばよかった。
I couldn't remember an important point during the exam. I wish I had taken notes on the teacher's explanation.
Analyze