I had a similar experience with a ZX-81 (and a TS-2000). What's interesting related to your "You cannot harm the computer in this way" quote is that I see that experimentation embodied in my kids (who grew up with a PC in the house) but also the anti-pattern in my mother and my in-laws who clearly didn't have a computer in the house until middle-age (note that I left my dad our of this category as he was an EE building embedded systems for instrumentation for much of his career).