n.
a painful memory that you look back upon with unexpected fondness, even though you remember having dreaded it at the time; a tough experience that has since been overridden by the pride of having endured it, the camaraderie of those you shared it with, or the satisfaction of having a good story to tell.
From hark back, a command spoken to hunting dogs to retrace their course so they can pick up a lost scent. Pronounced “hahrk.”