So, when we say something is an "odyssey," we mean it's a:
* Long and arduous journey: This could be a literal journey across continents, or a metaphorical journey through life, a career, or a personal struggle.
* Full of adventure and challenges: Expect unexpected twists, turns, and difficult situations.
* Potentially transformative: The journey itself changes the protagonist (or person undergoing the odyssey) in significant ways.
The word carries a positive, romantic, even heroic tone, even though the journey itself might be difficult. It emphasizes the narrative and transformational aspects of the experience rather than simply the length of time involved.