Remember the Crunchie ad's - the "That Friday Feeling" ones? Well, getting a new duvet cover is proving to have the same effect. It's just really nice to be lying under and on top of a new sheet and duvet cover combo, even though the duvet itself, and for that matter the pillows, are pretty old. Just that really fresh sheets feeling that still want to stay the same shape, plus new design that I chose myself (rather than use borrowed covers). Makes you want to stay in bed longer in the mornings, unfortunately; also makes it easier to get to bed/sleep at night though.
What is it about nice duvet's that just makes you feel so good when you're in bed? A human sandwiched in good quality cotton, cool and fresh against bare skin. Nothing quite like it. Well, not without involving more bare skin of whichever sex turns you on, anyway... ;-)