Modern Critical degrees lie at the boundaries between adjacent signs. So the degrees 29, and 0 of each sign. The traditional critical degrees separate the Lunar Mansions.
Critical degrees are not a safe place to be, like wandering between two warring camps.
A cusp between two zodiacal segments is likened to a destabilizing zone, where you teeter between both realms of experience, where you need to make a choice. This signifies (29*) a change of state, where you are in one realm or sign and can’t wait to experience the other. This is an impatient degree, like at the end of your rope.
Traditional critical degrees from the Lunar Mansions are:
Cardinal 0 degree 0′,
12 degree 51′,
25 degree 42′,
Fixed 8 degree 34′,
21 degree 25′,
Mutable 4 degree 17′,
17 degree 8′,