It's the one product by MS that stood out as being best-in-class straight from day one.
https://twitter.com/bbc_micro_/status/572313372345016321
The plastic which held them in place was always broken on the school computers :-)
In all seriousness though, I personally owe a great debt to Sophie Wilson et al for building computers and software that made it very easy to start programming the second after turning a computer on; A BASIC interpreter and an Assembler available instantly from ROM. I had endless hours of fun building parallax scrolling star fields by poking directly to video RAM and slowly rendering 3d scenes in Render Bender. It was just a shame that the computers were so expensive.
A friend of mine who had rich parents got his + 2 HD drives for his birthday, I had to take the long way around but eventually got there.
Without that machine I'm pretty sure my career would have started 5 years later.
I had a 1040ST and an Amiga 500 at the time as well (spot the geek) and the software wasn't that great on those platforms either IMHO. Even PDS on DOS was nicer to program in with the 2kg pile of manuals.
The killer was the rise of the PC and you know what; I'm glad it killed everything. Perhaps controversially, a couple of years down the line and as someone who wanted to get shit done back then, things like Windows 3, VB, Word, Excel, OLE appearing were clearly the future.