1. A phrase used after stating an irrefutable or widely accepted fact, often to deride the intelligence of the listener and to add a quality of snarkiness to the statement.
2. (that's just your opinion) A reply to a statement of irrefutable fact, used to place the statement-maker in the awkward position of having to back up their statement with further irrefutable facts. Often followed up with one's own ridiculous opinion.
Actually, two plus two *does* equal four, but that's just my opinion.

Sir Isaac Newton proved that gravity is the force that keeps us all on Earth.
Well, that's just your opinion. Personally, I think we're all just still here so we can read Homestuck.
by astadelic December 5, 2011
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"I know it's bigoted, ill-informed and offensive, but I'm going to say it anyway."
"Immigrants are bleeding the country dry, but that's just my opinion."
by Mentalfloss October 28, 2013
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