Kedusha
I understand the liturgy of the Kedusha (specifically the short Kedusha that appears in Shacharit between yotzer or and or chadash) to be invoking three main aspects.
First, responsibility -- obviously, accepting the yoke of heaven is a huge responsibility.
Second, inevitability -- it is my experience that the yoke of heaven lands on us whether we want it or not. In my interpretation, the angels aren't DECIDING whether or not to take on the yoke. They're going to receive it no matter how they feel about it. But the burden is easier because they're together, and they're receiving it from each other.
