Lamentation usually occurs when someone dies or a tragedy occurs. At the funeral, you could hardly hear the speaker above the wails of lamentation.
From the Latin lamenta, meaning “weeping” or “wailing,” lamentation means more than just shedding a few tears. Lamentation is when grief pours out. If you lose a nice pencil that's no cause for lamentation, but if you lose all your money in a stock market crash, that might be. If someone tells you you'll be late to your own funeral, you can always say: “At least I'll get to enjoy the lamentation!”