The sky is always sunny in San Diego -- until football season comes around.

Facebook measured all 32 teams in terms of "fan optimism" -- and the Chargers came in dead last.

By these numbers, Bolts fans are significantly gloomier on Facebook posts than any other NFL fans are. It doesn't make much sense; they've been one of the AFC's more competitive teams for some time now.

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Facebook's study might weigh the tone of stadium-related comments, too. Metrics might sink even lower in the coming months if that's the case.

(h/t Bolt Beat)