Title says it all. Got a phone call just a while ago and it was my manager asking if I could come in and work the overnight shift. I've noticed that this isn't the first time they ask ''are you busy” before asking if I can work. Obviously this is a way of them saying “you're not doing anything so help us out”. I told them I wasn't busy before she asked if I could come in and now feel like an ass for saying I can't come in. I only want to work my scheduled (contractual) hours and nothing more. This leads me to come asking you guys, what should one say the moment that “are you busy” gets asked?