Significance of Dates

Today is 11-11-11, my birthday this year was 11-1-11, some more recurrences like this happened this year, last year and will happen next year too. Why are we all happy about this, and why are all my BB contacts, facebook contacts, linkedin contacts, twitter contacts, whatapp contacts and the umpteen number of contacts celebrating these dates and mentioning them all the time? Why are numbers make huge differences and provide happiness or sadness in people's lives? Why are we happy to celebrate our birthdays when we were young, and sad that we are getting older when we are old. Why do we celebrate anniversaries in the opposite ways? why do we link what is happening in our lives to numbers and always have associations with numbers? my car number, number of cars I had during my life, bank account number, phone number or numbers, number of bank notes I spent on a certain item, number of bags I have, number of shoes I have, or would love to have (that is my daughter's line), number of wives I want to have (that would be my husband's line hehe), number of certificates I want, number of houses that generate me too many numbers of bank notes. This can go on and on. so you see, we are always linked with numbers?

What is the significance? Can someone tell me?

I picked for you some links: World set to celebrate 11.11.11