X may have wanted to share his thoughts for a while but it happened on that particular occasion, either out of sheer boredom or simply wanting to express oneself. Y may have always wanted to go in for short hair but could not because of some restrictions - familial or otherwise. But, she did it on that particular day.
Sometimes, change comes to us - we are not expecting it - and we may not like it - but it comes all the same. Our entire life goes through the motions as we adjust to the changing scenario. And sometimes, we need to bring change to our lives. When we bring change into our lives, we always think that we control all the aspects. Actually, change is unpredictable as always - whether it comes to you or whether you bring it to your life. In fact, the unpredictability and the energy it brings is the best part about change. I am not saying its easy but you have to and so why not with a smile :)
On another note, I saw Mystic River, it had be bawling! Seriously! Great movie. Watch it when you have the time.