The use of 'Z' in "DayZ" is meant to represent the number of days a player has survived. This is reinforced by the Day 'Z'(where Z is the number of days you have survived) that show up at the bottom right hand of the screen. On topic, I read 'DayZ' as "daze". Side note, I'm from New Zealand and I only use the 'zed' pronunciation when saying NZ like most of the people I meet. Adding to that, most drunks also get aggro'ed quite easily (does not like loud noises) and has a difficulty seeing/hearing things properly.