I know just what you are going through!
Friend 1:
"Where can I get a bird like Emmi?"
My reply:
"Didn't you ask me to take your daughter's hamster a few months ago because it was too much work?"
Friend 2:
"I just asked my husband if we could get a Green Cheek! He said yes!"
My reply:
"You have six cats! Six! They kill the outside birds! They bring them to your door step!
Friend 3:
"I'm so getting a bird now!"
My reply:
"You are having a baby in two months...really?"
Thankfully none of my friends ever got a bird of any kind. I'm seriously scared to post anything cute on Facebook about Emmi anymore because of this problem. I'm not saying that my friends would make horrible bird keepers, but I do know them well enough to say that some should not have any pets at all. Or plants for that matter.
I would just do what you can to educate. Sound excited as you go through the costs of the "highly specialized diet" and "daily responsibilities." Then go through the dangers like metal poisoning, sickness and oh yes...vet costs! That normally weeds out the goldfish/hamster type people. If all else fails, talk obsessively about your bird like it's your child one evening. Become the person they don't want to be. Lol
Passive aggressive, yes. But it sometimes works! So far, no pet birds for my friends!

My family: "Emmi" Green Cheek Conure (12/15/2012), One husband, two step kids, and one baby boy born in January 2015!