It is okay to sleep in. Especially on a Monday. I mean.... how often do you get the chance?
It is not okay to not shower and lounge around in 2 day old clothes munching on pretzels and drinking warm Gatorade.
Why is it not okay?
Because some asshole will pull the fire alarm and you will be forced to walk out amongst your peers in your mis-matched red sweats and purple hoody and shower flip-fops. Not to mention the zit cream you forgot you had on your face. You will be embarrassed beyond belief and hope to god no one will notice your greasy unwashed hair. As you cross your arms across your chest you don't even want to think about them noticing you are wearing your oldest stretched out most comfortable sports bra. In fact at this very moment you wonder why you have even kept it, it offers no support at all.
It's okay to have a shitty relaxing slacking sort of day. But please keep in mind you might have to make an unexpected public appearance.