A phrase used when you have nothing else to say, during an awkward moment, when asked a personal question, or when you dont feel like having a conversation with somebody. It means what ever it is needed to mean at the time you say it.
Matt: "I found unfamiliar stains on my sheets"
Jeffery: "That sucks."
Matt: "I saw you on the nanny cam"
Jeffery: "i dont like change."