あげく（に）Eventual bad result after a long process
あげく（に） introduces what eventually happened after a long, difficult, excessive, or frustrating course. The result is normally disappointing, troublesome, futile, or anticlimactic.
How it works
The first part presents a process that took time, involved repetition, or caused difficulty. The second part gives the endpoint and usually suggests that all that effort, delay, or trouble led somewhere unsatisfactory.
Verb and noun patterns
何度も修理を試みたあげく、結局その時計は処分されることになった。
After repeated attempts to repair it, the watch was ultimately marked for disposal.
AnalyzeThe repeated repair attempts establish a prolonged effort, and disposal is a disappointing endpoint.
長時間の議論のあげく、会議は結論を出せないまま終わった。
After a lengthy debate, the meeting ended without reaching a conclusion.
AnalyzeHere the noun names the difficult process, while the result makes the time spent feel futile.
What makes it natural
Processes such as hesitating, worrying, debating, negotiating, making repeated failed attempts, or continuing an excessive action fit especially well. Words such as 結局 and 散々 often reinforce the sense of a drawn-out, frustrating course.
An especially exasperating endpoint
散々周囲を振り回したあげくの果てに、彼は計画そのものを投げ出した。
After putting everyone through endless trouble, he finally abandoned the whole plan.
Analyzeあげくの果てに heightens the speaker's exasperation at the final result.
Choosing the right endpoint expression
Use 末（に） when you want to foreground a long process without adding strong frustration; it works naturally with positive and neutral results. Use ずじまい when the key point is that an intended action never happened. By contrast, あげく（に） reports the eventual result and adds frustration or disappointment.
More examples
何軒もの店を回ったあげく、欲しかった品はどこにもなかった。
After going around to shop after shop, the item I wanted was nowhere to be found.
Analyze就職するか進学するか悩んだあげく、どちらも選べず、一年間休むことにした。
After agonizing over whether to get a job or continue studying, I could choose neither and decided to take a year off.
Analyze度重なる交渉のあげく、契約は白紙になった。
After repeated negotiations, the contract fell through.
Analyze言い訳を重ねたあげくに、彼は責任を部下に押しつけた。
After piling excuse upon excuse, he ended up shifting the blame onto a subordinate.
Analyzeパスワードを何度も入力し直したあげく、アカウントがロックされた。
After reentering the password again and again, the account was locked.
Analyze散々迷ったあげく、その日は何も買わずに帰った。
After endless indecision, I went home that day without buying anything.
Analyze