せっかく折角sekkaku
1.
A word that conveys the feeling of regret or disappointment when efforts or expectations do not yield the desired outcome, often used to express apologies or sympathy for disappointing someone despite good intentions.
2.
A term used to emphasize the importance or significance of an action taken with great effort, particularly in contexts where one wishes to acknowledge the value of that effort.
3.
A phrase that reflects the rarity or exceptional nature of a situation, suggesting that it is unfortunate when such opportunities are wasted or not fully appreciated.
Example:
せっかくの苦労もあだになった。