Please feel free to ignore the following parenting rule: Enjoy every moment! It goes so by quickly. Because I can almost GUARANTEE you that there will be days with your children you do not enjoy.
All-family stomach virus day? Not enjoyable. My kids coated the brand new couch we saved for over a year for in Sharpie day? I give you permission to go ahead and despise this day. My child learns to scream the word "NO" at top volume? Go ahead and take a week off from enjoying parenthood when this happens.
If you take the pressure off yourself to delight in every single instant of your childrens' existences you'll be a better parent and a saner human. And there will be plenty of moments to enjoy, don't worry. Just not 'My kids have learned how to open the refrigerator and have now hidden broken eggs all over the house' day. That day's gonna be really, really bad. Be warned.