You are observing special days and months and seasons and years!

Romans 14:5
One person regards a certain day above the others, while someone else considers every day alike. Each one should be fully convinced in his own mind.

Galatians 4:11
I fear for you, that my efforts for you may have been in vain.

Colossians 2:16
Therefore let no one judge you by what you eat or drink, or with regard to a feast, a New Moon, or a Sabbath.

You observe days, and months, and times, and years.