Monotony is comforting. Maybe, that is why it gets boring after a while. There is little to no adventure in it. At times, it gives a feeling of being stuck which makes us feel suffocated too.
Routine is a monotony. It is a repetition. Maybe, that is why people wish to break from their routine after conforming to it for a while because they wish to break the cycle.
Monotony is such a trait of life that everyone desires but cheers up in all occasions of escaping it, even if just for a while. Though, monotony gives a sense of stability. This stability gives confidence, reassurance and peace of mind to an extent. So, sometimes, monotony is necessary too and is the most pleasing thing for us at that moment.