Z to A: X

X is great
Talk about your exes and you can get in trouble
You can't have an ax to grind without an X.
X marks the spot, but I still haven't found the treasure.
You can't fix it without an X. Can't send a fax without an X.
However, with out X there would be no tax.
Sadly with no X there would not be a sax.
X-rated could be too revealing.
I could go on about X but I could get in trouble...