Spur of the moment purchase - an impulse buy often without thought or planning.
A 'spurchase' may lead to buyers remorse, and depending on what you spurchased, it may lead to ridicule, embarrassment and a trip back to the store for a refund.
The initial demand for a citation, often deployed as a conversation-stopper rather than a genuine request for information. The sourcepost is planted firmly in the ground of "I don't have to engage with your argument until you provide a source," regardless of whether the claim is common knowledge, obviously true, or literally happening in front of you. Once the source is provided, the poster can either ignore it, declare it biased, or—if they're particularly committed to bad-faith arguing—move the sourcepost to a new location. The sourcepost is the first line of defense for people who don't want to think, just to win.
Example: "She said water was wet. He immediately planted a sourcepost: 'Source?' She said it was literally the definition of wet. He said 'source?' She linked to a dictionary. He said dictionaries weren't reliable. The sourcepost had done its job: derailing the conversation and establishing that nothing would ever be sufficient."