I go to church every Sunday possible. Meaning, apart from sickness, injury or some sort of emergency, I am at church Sundays and Wednesday evenings, worshiping and praising God with my church family. Congregational fellowship is a true blessing from God, and a great way to grow in and learn of our Lord and Savior.
Will not going to church make God upset? Maybe, maybe not............depends on the reason one isolates themselves from the family of God. You would have to be more specific in that area. Some people are home bound and due to physical reasons can't go to church, but they can have church where they are. Just as some choose to attend a home church rather than a church outside of the home.
Why are you asking?