Phrases Phrases for Expressing Regret

I should have...

Meaning

Expressing a missed opportunity or a mistake.

Translation language

John: The deadline is tomorrow, and I haven't even started.
Alice: Oh dear.
John: <b>I should have</b> started weeks ago. I really messed up.
Alice: It's happened to the best of us. Still, try to complete as much as you can today. I have had the same problem; <b>I should have</b> planned it better.