To help get this thread back on track I can share a similar experience a few years back. I used to build primarily WWII German armor, but lost the luster. My last two kits were the Fehrmann Tiger and AFV Sturmtiger. They are about 90% finished, but the meticulous detailing made it more of a chore and the fun was lost. I couldn't explain what happened to me.
I then picked up an airplane kit and it was like a large snowball being pushed off a mountainside. I am back to being out of control on building my stash and can't wait for finding extra time to work on my kits. I still have many armor kits that I know I will get back to someday, or sell on ebay.