I moved to a more rural area with many 4 way stops last year. I really had no idea but I thought you took turns in a clock like direction. One day, I finally broke down and asked my husband and he explained the, much more logical, rules to me. Luckily, I didn't kill anyone.
Don't feel bad...at least you prolly know what to do when the stoplights are blinking red...you see alot of "Darwinian moments" then too.