It is good to study God's appointed feasts from scriptures like Leviticus 23 or Exodus 12, for example. They are more likely to be of value in growing in understanding than conforming to many cultural practices and holidays outside of scripture. However, during the various Christmas and Easter celebrations and traditions of different cultures one sometimes hears scriptures being read, from Matthew 2, for example, or Matthew 28, as another example. Any scripture can be of value, like those about Christ's birth or his resurection. Hymns are often valuable as well. Just going to a cultural tradition or a cultural holiday does not make you saved nor does it make you unsaved, and is never a means to be saved. Not even ritual enactment of the Leviticus 23 holidays makes us saved, or makes us not saved.
If we look at the feasts which the Lord chose from Leviticus 23, we should understand that to truly "keep" a feast does not means to follow a set of physical rituals at a particular date, like to find a real kid goat on a special day of the year and go kill it, for example. Rather, the rituals described are patterns which point to Christ and his salvation plan. The rituals themselves are just a shadow of the real thing. The kid goat that is killed is just a picture of Christ. If you understand the message, you don't have to kill a goat every so often to be in obedience to God. In fact, killing a goat on a special date will not be a means to salvation. The real thing is simply to be in Christ, to accept that he was the one slain for us.