Ok. I think I understand what you mean. But all the risks what could happen and bad ideas aside: it still is my system and responsibility to do with it as I want.
Absolutely it's your responsibility, but the very fact that you're here means that you use the internet, and you're leaving a gaping hole in your system security since no password allows the possibility of malicious content bypassing Apple's security models (not entirely, but you're certainly lowering the bar).
One of the reasons why Mac OS X beat Windows on security and malware issues is that it's been much, much harder for an hacker to install malware without interaction by the user - on Windows it was pretty trivial (just visiting a web site was sometimes enough). The password gate adds a layer that causes the user to pause and think about what they're doing. With no password you lose that protection.
But as your said, it's your horse...
As for changing the password - System Preferences -> Users & Groups -> [account] -> Change Password