Lost in thoughts

I have almost never experienced the feeling of being lost in thoughts and forgetting to do something.

But, I'm quite surprised that I have become lost in thoughts and forgot to get off the bus after pressing the bell. It's not the first and only time. There were times I forgot to get off at a station while on the train as well.

I don't know what's wrong with me actually. LOL! Maybe there arose so many things I need to contemplate over? Perhaps.