I absolutely used to make impulse purchases all the time. However, I made a real effort this year to establish more self control as my collection had grown to epic proportions! For the most part I've done a good job with the self-control thing...except for one slip-up in May when that same "Mario" guy (responsible for MELGAR & Arnold starting this thread) posted some photos of the MTH NYS&W GP40 that he just picked up at JR Junction.
One look at Mario's photos and I convinced myself I just had to have that engine. My new-found self control went right out the window, and I immediately ordered it from @JR Junction Train & Hobby. That turned out to be my first MTH scale-wheeled locomotive purchase, so in all seriousness, I'm very glad it happened!