It'll be very largely irrelevant unless you're Australian, and a fan of particular teams, but I can think of three instances that scarred me big time. Two in the Australian Football League (one which took 21 years to redeem, the other is as raw as it was 8 years ago) and one in what is now called the NRL (rugby league), that only took 2 years to rectify.
I also know what it feels like to experience, as a fan of course, a team's first ever title. I'm hoping 2026 will be the second time, because the first was 45 years ago, and I'd like to savour that feeling one more time.