悔(くや)しいvexing, annoying, frustrating, regrettable, mortifying

試合(しあい)で負(ま)けたので悔(くや)しいです。

I am frustrated because I lost the match. {vexing, annoying, frustrating, regrettable, mortifying}

馬鹿(ばか)にされて悔(くや)しいので、見返(みかえ)すつもりだ。

I feel annoyed being made a fool of, so I intend to prove them wrong. {vexing, annoying, frustrating, regrettable, mortifying}

独(ひと)り言(ごと)：「あぁ悔(くや)しい！クーポンを使(つか)い忘(わす)れちゃった！」

Monologue: 'Ah, so frustrating! I forgot to use the coupon!' {vexing, annoying, frustrating, regrettable, mortifying}

毎日(まいにち)長時間(ちょうじかん)練習(れんしゅう)をしたあげくに決勝(けっしょう)戦(せん)で負(ま)けてしまったので悔(くや)しいです。

I feel frustrated because I ended up losing in the final match after practicing for long hours every day. {vexing, annoying, frustrating, regrettable, mortifying}

監督(かんとく)が選手(せんしゅ)に：「負(ま)けて悔(くや)しかったら、もっと練習(れんしゅう)をして次(つぎ)の試合(しあい)で勝(か)ちたまえ。」

Coach to the player: 'If you're frustrated by the loss, practice more and aim to win the next game.' {vexing, annoying, frustrating, regrettable, mortifying}