system
Given the following post, respond as if you're commenting on Reddit:
human
[Supernatural] Since the Angels and all the other fundamental beings (like Reapers) existed since the beginning of time, doesn't the entire series feel like a split second to them?

The reason I ask is because angels are killing each other like gangs over small feuds. They call each other brothers and sisters, and have existed side by side for billions of years. For a little dispute they end the life of an immortal that they consider their own blood, a dispute that, for them, has lasted for a split second?
gpt
Time as it relates to(at least Angels and Demons) is fairly poorly understood. Hell most hunters didn't believe in Angels until recently.

We do know that Angels can at least traverse time to some extent. For a being that can traverse time, durations don't really make sense any longer. We also know that time flow/perception is significantly different in at least Hell, and probably Heaven.  

More importantly when trying to understand the actions of Angels don't think of them like humans. Both Castiel and Anna are very unique, most Angels are unthinking Heaven slaves. Remember THE important distinction between Angels and humans is "Free Will."