Because we might as well get to the subject of Odin's single eye sooner rather than later!
But first, a short personal anecdote:
I went to a primary school where the main entrance corridor had (has?) one wall decorated with coloured glass and metal, depicting some figures: There were some animals in a tree, and a lake, a dismembered eye, and two men in conversation (one of whom, if memory serves, had a tail). I walked past it each and every day for years and years and years, and I never particularly heeded it, never reflected on it, it was just big and slightly garish and there
Then I entered my Norse phase, read every myth I could find, trawled the libraries for more. A year passed. One day as I was standing in that corridor, probably waiting for my best friend who was equally obsessed with Norse mythology, I leaned against the opposite wall and looked at that decor for the billionth time, and finally... IT CLICKED. I REALIZED. I probably squealed in surprise. That image, those characters - they were from this myth!( With some additional notes on early Æsir society and Odin's younger days )
Congratulations, now you know why some of Odin's many, many names are Hoárr ("one-eyed"), Báleygr ("flaming eye"), Bileygr ("shimmering eye"), and Blindi ("blind"), not to mention the kennings
Vinr Lopts ("friend of Loki") and Vinr Míms ("friend of Mímir").
And if you're starting to ponder things like "Wait, so the Æsir and the Jotuns aren't just mortal enemies? It's not just a question of the noble, clever gods versus the ugly, stupid trolls?" you're doing very well