Not the Kilcarr kind of creep

, but growing beyond what you expected. Have you had it? I sure have. I'm finally done, except for a few things, emptying out my house so I can put it on the market. As I boxed up my collection, I remembered back when I first got back into GI Joe. I'd sold off most of my childhood collection, except some sentimental pieces, back when I turned 18.
Fast-forward to my mid-twenties and I was back at my folks' place, visiting, when they asked if I would get the rest of my stuff out of my old closet so they could have the space. I said sure, and taking the stuff home made me nostalgic. I then regretted having sold off my collection and started looking around for replacements. I'd made a vow to myself and my then-wife that I would only collect figures and no vehicles, and only the 3 3/4" of my childhood, since there was no room in the apartment at the time for much more. This worked well for a while until I saw an auction for a bridge layer, one of my childhood favorites, both for the vehicle and Tollbooth, so I bought it, saying to myself, "Okay, so I want that vehicle, I really enjoyed it as a kid and would like to have a replacement."
Then we moved into the house, and I then had a whole room for nothing buy my collectibles. I've never been a fan of 'rows of figures', so I wanted to have dioramas for displaying my collection. This led to more vehicles and play sets. It also led to army building of figures and vehicles, for display purposes.
And now that I've had to go through and touch every piece of my collection to box it and move it, I've realized my small collection that was supposed to be just figures has grown to include almost as many vehicles as figures and I also have a lot of Joe related items and collectibles that were definitely not part of the initial plan, but kind of organically crept into my collection.
Have you experienced this, and if so, how'd it happen?