Something I found cool with the /wait 1 command is to optimise the smoothness of popping off GCD buffs. Take a standard macro that pops Foresight before you do Heavy Swing:

/macroicon "Heavy Swing"
/ac "Foresight" <me>
/ac "Heavy Swing" <t>

Now there's nothing fundamentally wrong with that macro. If you run up to a mob and spam it, the first time you press the key you'll do Foresight, which ties up your animations for about a second. Then the second time you press it you'll get the Heavy Swing, albeit a little delayed.

However, if you make the macro like this:

/macroicon "Heavy Swing"
/ac "Heavy Swing" <t>
/wait 1
/ac "Foresight" <me>

You run up to a mob, hit the button once, and it will do the Heavy Swing and then will pop Foresight DURING THE HEAVY SWING ANIMATION. This means you don't get tied up with the animation delaying your initial cast of Heavy Swing, and you can still hit Skull Sunder after 2.5 seconds with no Delay because the animation of Foresight is over before the 2.5 seconds ends.

There's many other situations where macroing an off-GCD cooldown with a /wait 1 after an on-GCD attack just makes the rotation far smoother. The game is optimised to be able to slip off-GCDs in between 2.5 sec cooldowns without interrupting animations, and /wait 1 lets you do this easily.