Which particular definition?
- Belief in and reverence for a supernatural power or powers regarded as creator and governor of the universe.
- A personal or institutionalized system grounded in such belief and worship.
- The life or condition of a person in a religious order.
- A set of beliefs, values, and practices based on the teachings of a spiritual leader.
- A cause, principle, or activity pursued with zeal or conscientious devotion.
Seems like even if you don't believe in the supernatural, you could still be quite religious (#5).
I don't have a problem believing or worshiping God, or worshiping Him with others, because it's what I believe (not what I'm trying to earn). I also reserve the right to disagree with leaders (and I have done that), to keep from being anyone's slave.
If religion is only about activity to get God's favor, then it would be overwhelming and exhausting; it would be a source of anxiety as well (which doesn't help social relationships).
bebu