I wouldn't say that your purchase was all that ridiculous. Sure, it's a rather expensive coat, but as long as it is high quality and you actually use it, it's actually a good investment. You're going to need a coat, especially if you live in the UK. Might as well be a good one and something you like.
As for me, I really don't cave into my fangirlisms much. I cave into my hobbies a lot though. I can't tell you how much I sink into my baking hobby. @_@ Oh well, at least my cupcakes make other people happy which is something I suppose.
I did placate my ex's fanboy. He is a big Paul McCartney fan, and had gotten a Wii for Christmas. He wanted Beatles Rock Band and the limited edition controller that looks like McCartney's bass. I searched all over for that thing on the internet and I finally found it. Between the controller itself, the shipping and correcting a mix-up with the shipping, it cost me around $170. He broke up with me two days before the controller got to my house. << Lesson learned.