I think many of us struggle with these issues. For myself, I was older when I left the organization, so I felt no need to go out and sample all the worldly things I didn't do as one of Jehovah's Witness. I had never taken drugs, smoked cigarettes, or had promiscuous sex, and I wasn't going to start doing those things. I guess at the end of the day I still considered myself Christian, as that was how I was raised, so I continued to live my life by those principles Jesus said to "do unto others as you would have them do unto you". This golden rules is all that is needed to determine the right thing to do in any given situation.You do not need to be Christian to understand this basic principle.
I also still believe in the fruitages the spirit, love, Joy, Peace, kindness goodness faith, mildness and self control. I try to apply them in my life.
On the other hand, I saw no reason to not celebrate holidays. It doesn't violate the golden rule, and if done using the fruitages of the spirit, it can be a very good thing.
It seems to me the WTBTS is so obsessed with laws and control they have completely lost the meaning of Christ's sacrifice, and are no better than the Pharisees. Its all so simple, really.