Halloween costumes. Why do I wait until the last second?

Why is it that every year I wait until the last minute to work on their costumes?  They insist I make them their costumes (which I secretly love doing anyway), and I know well ahead of time what I need to make, but I always wait until the week of (or day of) to make them up!
Last night I was up into the wee hours of the morning crafting costumes for my boys.
Timmy has wanted to be Mario for about 6 months.  I did crochet his hat up about a month ago.  The overalls I whipped up today.  Voila!  All done!

Niko wanted to be Luigi at first.  I thought it was going to be great!  A Luigi and Mario walking down the road together!  It'd be perfect.   Then Niko saw the postcard I made with Timmy during our art class here at home and he insisted he HAD to be Frankenstein.  Ugh.  Really?  But everyone is Frankenstein!  No changing the boys mind, though, so I had to go with it.  I sewed up his jacket last night.  I made the head/hat  and the collar with the bolts sticking out of it last night as well. 

Adrian has said he wants to be a rocket ship since the ride home from trick-or-treating last year.  I was really dreading this one.  I really just couldn't figure out how to best make it.  I thought about poster board and then knew that wouldn't work because he would need to be getting in and out of the van and sitting in his car seat in the van while we went TOT'ing.  It had to be something soft, but I had to be able to make it look like the structure of a rocket ship. 
In the end I decided to just use fleece.  Made a porthole for his face to look out.  Made a cone out of plastic canvas and put that in the tip of the rocketship to sit on his head like a hat.  Stabilizing legs made of plastic canvas on the outside and red and yellow tulle coming out the bottom to signify flames.  It is NOT my best work.  Not by far.  I'm really not very pleased with it at all, but HE loves it.  And that is who I wanted to make happy.  So here is my little rocket ship!