It just grinds my gears...
I need to go out of my way - sometimes having to go as far as threatening to quit - to get Halloween and my birthday off (what are the closest things to "religious" holidays for me) but if someone is Muslim and wants to come into work late for a month it's not an issue.
I loose money because I'm forced to take time off work over other peoples religious activities. It also negatively affects people who could be using the services provided by places of employment, who are unable to due to Sky God Day and Sky God Day Eve.
This certainly is true. I'd like to take off on 4/20! Or the day after.