[QUOTE=DJ Motorbike]
I was into model rocketry as a kid. I had few failures. They aren’t that hard to build with a little patience. It made me get a few bad ideas in my head that I’m glad I never actually carried out. For instance, I thought it would be a really cool thing to use a primary stage engine that has an explosive charge at the end of it’s fuel that is meant to ignite the second stage.
Well now, wouldn’t it be just nifty instead of having the explosive charge ignite a second stage have it ignite an explosive instead? Ballistic Missiles! Cool! I got as far as taking apart firecrackers for the gunpowder before my older brother told me I was going to kill someone or start a fire and made me stop. The Jerk.
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Thankfully, I did not have an older brother. My model rocketry career ended abruptly one day, when the rocket fell over on the launch pad, the nose cone, stuffed with all sorts of interesting things, ignited, and about 20 people were engulfed in the resulting groundburst. I came to my senses in time to see the rocket engine bouncing off across the surface of the lake. No serious injuries, but the time was right for me to move on to other things.
[QUOTE=Johnny L.A.]
The launch control has a ‘safety key’. (I think I was using one piece of a little wire-puzzle – the one where you have two straight wires with loops at the top and you have to separate them – really simple puzzle.) I left the key in the control. Only on my previous launch the launch button, being cheaply made of plastic and square in shape, remained depressed in the ‘launch’ position completing the circuit when I hooked the leads to the ignitor.
Always remove your safety key before preparing a rocket for launch!
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Launch control? Safety key? Oh, I see. You had one of those fancy ‘store bought’ launch systems. 
I had a lantern battery, wire, and a doorbell button. It actually worked well because you could easily detach the battery and safely approach the rocket.
And whatever you do, do not tape your rocket to your ‘Little People’ car in an attempt to make a rocket car. If you do, be prepared to run for your life.
Ahhh, good times.
I can’t add much to what others here have said. Like many other guys, I was into model rockets for a few years in junior high and high school.
Then, 25+ years later I took it up again for a couple of years, and got much more serious about really making them look good, working hard on the sanding, doping, and painting. (I was also doing some plastic kit models at about the same time.) It was very satisfying to work so hard on making something look as perfect as you can and having it turn out well.
But the really challenging thing about model rockets, as opposed to ordinary plastic kit modeling, is that once you’ve made your perfect model, you have to fly it and risk seeing your beautiful baby crash and burn. Literally! It’s cheating to build a model and not fly it, and I’ve never done that. It’s hard, but you learn a lot about careful preparation, taking risks, and living with loss. But the exultation of a perfect, damage-free flight is great.
Model rocketry: it’s more than just a hobby. It’s a life lesson.