Eyeslice, having a yearly routine of doing things is a good thing - unless you happen to be in a cult.
The Watchtower is like a huge clock, every time the big hand reaches another hour, there is another activity.
12PM, 1PM, 2PM, 3PM
In reality, once the big hand gets back to the 12 again, you look back over a year and maybe ask yourself some questions.
What have I really accomplished in a year?
The WTS doesn't encourage you to take up a hobby (unless your Bible reading is that deep), they don't encourage you to go to school and get an education, and they are against worldly careers.
There is NO SINGLE special day that the Watchtower Society has to get "everyone together" just to celebrate life.
There are no celebrations like you said, hence there is no wrapping of gifts and exchanging of gifts, except at showers and weddings.
There is no notable date in Watchtower land where you could find a reason to celebrate.
And the Memorial is just another recruitment exercise.