“celebrate”

I’ve been thinking about this word, the action, and meaning a lot this week and wondering things like why we celebrate birthdays and why do some people love being celebrated and others dread it?  I don’t know the answers but thanks to dictionary.com I at least know the definition:

Celebrate-

1. to rejoice in or have special festivities to mark (a happy day, event, etc)

2. ( tr ) to observe (a birthday, anniversary, etc): she celebrates her ninetieth birthday next month

3. ( tr ) to perform (a solemn or religious ceremony), esp to officiate at (Mass)

4. ( tr ) to praise publicly; proclaim