I confess that it irritates me to no end when people say:
"You won't understand till you have children"
"You won't understand till you are married"
"You won't understand till you are in a long-term relationship"
I'm married, and I try not to say annoying shit like that to my single girlfriends. And being married is awesome, but so is being a single and a confident woman.
Being married, or having children, does not make you a happier person. You CHOOSE to be a happier person. Lots of unhappy, fucked up families. There is no one who can make you unhappier then a family member or loved one.
And another thing that irritates me, though I'll probably act like it one day: Acting like you're the first woman who's gone through pregnancy and discovering parenting truths for the first time ever.