Hold on there a minute Mr. (Mrs? Miss?) Shark...I answered your question but you forgot to answer mine!
Lev 23:2 "Speak to the children of Israel, and say to them: 'The feasts of the LORD, which you shall proclaim to be holy convocations, these are My feasts.
I observe these days because I love Jesus and want to honor him by letting his indwelling spirit observe HIS days...
BUT I presume you observe Christmas and Easter...why? If the feasts of Jesus Christ, in scripture, are "nothing IN COMPARISON" then surely these man made days are less than nothing IN COMPARISON...right? :-).
And your question implies that I should STOP observing them. So why don't you stop observing the days that man created?
What day has man created? Hasn't God created them all?