Rebooting reloads all the programs again

Sometimes when my macbook gets slow I want to reboot. However, after I restart the computer all of the previously running programs are RELOADED! This pretty much defeats the purpose of the whole point of rebooting - which is to start with a clean slate. How do I tell the mac that when I reboot, to just reboot without loading all programs I had open? Note: I assume there are programs that always get loaded at start-up; I am not referring to this.