Hi Garrett, I left 26 years ago and I do join in with most of the holidays now. The first year we didn't celebrate Christmas because we still thought of it as being of pagan origin, but we put up a tree and bought each other little presents the following year. Now I buy Easter eggs, birthday presents and I let my daughter go to Halloween parties.
Why? I was so damaged growing up as a JW and not being able to join in holidays at school. We are social animals, we need other people. I decided to let my daughter feel normal, not weird, 'no part of the world'! We are a part of the world, trying to be separate was very bad for us psychologically.
Does it matter that things have pagan or even Christian origins? I no longer believe in God and I see religion anthropologically, it was part of the development of humanity, it helped people cope with the harsh realities of life.
It's fun being'normal' and joining in. Many holidays have become commercialised but I just join in as much as I want to and leave whatever I don't like. I can also be relaxed at work during holidays, give cards, eat mince pies, have a birthday drink with colleagues, go to the Christmas party. As an ex- JW it has made my life so much easier now.