DH is easy to convince even though he always complains about the cost... I just tell him every year we never know, DD may not want to go again next year... She should go while she still loves it (never mind the fact that she will ALWAYS want to go!) (DH has never been, he always wants to stay home with "his" dog)
I can't talk about Disney with my sister at all, she thinks we are excessive and does not want her children knowing we are going AGAIN... I think because she doesn't take them, and they would love to go. I have tried to talk them into going WITH us, but she has a million reasons why they can't (one of them being that the kids don't really enjoy it... someone should tell her kids that! She also doesn't want to go because her kids are fair skinned and they might burn, it is too hot, her favorite hotel doesn't exist anymore)
Then there are the people who can't understand that I LOVE Disney... they think I should just be taking my daughter and not be so gung-ho about going. Hey, I wear ears, meet characters, and take millions of pictures... plus I love the planning aspect. (I don't understand people who wing it all the time... no ADRs, no idea what park they want to go to on which days... I am not obsessive, well I don't think I am... I plan my ADR's, my park days, schedule pool time, know where I want to be when the fireworks/parades start,and have alternative plans for rainy days)