Why did he ignore my friend request?

Few months ago I added a guy on Facebook and he totally ignored my request - neither he accepted or declined it. This guy attended the same university as me and we had few common lectures during the past two years. Few times I noticed him looking at me so he has to know that I am not a random stranger from the other side of the planet. In real life I was too shy to express my interest so I added him on Facebook. A week ago as a mature grown up I blocked him because I understand the message: not getting a response is a response too.

I know it’s a typical first world problem but I don’t understand why we had that many eye contacts if he wasn’t interested.

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1 y
We only talked once.
Why did he ignore my friend request?
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