l' d say the period when you have a bit of financial freedom and still able to date / socialise / burn the candle at both ends without it looking like a midlife crisis. or the minute you buy a volvo, it;s game over i'm afraid
Twenties, but sadly you do not realise just how good it was until it is gone. That said, I think my mob (Gen X) and the boomers had it even better than today’s crowd. We actually had freedom.