Why is it creativity comes at the most inopportune time...

It never seems to fail that my most creative ideas and best paragraphs seem to be written in my head. While this is not necessarily a bad thing. It always seems to happen when I am the furthest away from my computer or a paper and pen. It drives me insane mostly because I think to myself that I will be able to recall it when I get to my computer. However when I get there it is gone, often to never materialize again. I have resigned to carrying a digital recorder with me so that I can start talking these little bits of gems out when they come. I'm sure you can imagine the looks I get when people drive by me and see me talking to myself.