My hobby is model engineering and it's quite stressful when you're hours or days into a part and every new operation risks ruining it. Not only have you wasted

My hobby is model engineering and it's quite stressful when you're hours or days into a part and every new operation risks ruining it. Not only have you wasted that time and effort but also the material, and if you stuff it up you get to do it all again for no benefit at all - it's all cost and loss. Read a drawing wrong? Another chunk of time & metal wasted. It's a frustrating and expensive hobby. That's what I think is so great about software - almost nothing is irretrievable and even if it is it's not that big a deal to redo, other than for whoever paid you to make those mistakes! But software is also ephemeral and for all but a few of us it's hard to point to something and say 'I made that, it's works, and it's really cool' and have other people get it. When you drive off on the steam loco you just finished it has a bit more impact! Even my teenage son said "it's pretty cool to build something that moves under its own power".