OS X keeps rebooting by itself
But, I now I feel really dumb, after seeing you suggestion I've started googling for my issue plus log out instead of reboot and found the issue: automatically log off after x minutes of inactivity was set to 60 minutes. What I find most puzzling other than this being set in the first place is how the hell did this I inherit this setting on a clean install I did of Mavericks. My sincere thanks for your help, guys, I'm going to sit in the corner for a while :)