Earlier today, I was doing some work on my Macbook Pro and then closed it, so it went to sleep. About an hour later, I opened it, and tried to enter my password. For some reason, I couldn't login despite making sure that I was entering the correct password. I turned caps lock on and off several times, making sure I wasn't entering my password completely upper case. However, when I restarted the computer and tried to login, it worked. I'm just curious as to how this happened.