windows 8 upgrade huge pain in the ass

OK I bought and upgrade of Windows 8 Pro (form Win 7).

It all went well, installed and after restart (hour of my time) it said: "Sorry could not install, fuck off".

Ok, so I tried another time, again nothing. So what the hell lets try clean install. Backed up everything, formated the disk, installed like the charm.

"Please activate the copy" - it said. OK, i inserted AGAIN the valid key. "Sorry, you have the key just for the upgrade and I know you made a clean install, so fuck off and thanks for your 30 euros."

WHAAAT?

So again I installed (clean) Windows 7, then I did not bother with activating with my original key. Upgraded straight away and in worked like a charm.

This process overall was so big pain in the ass that I spent half a day with it...

Why I could not simply:
a) installed it without any fails for the first time - obvisously huge error by Microsoft and I am not the only one who has problems with upgrade.
b) If I suceeded with the clean install - it should have asked - "Ok so you made the clean install of Win8 but we trust you have a valid Windows 7 so please look on your computer and write us your key of WIn7 first. We make it valid and NOW insert your bought key for Windows 8"

And this company is worried of losing customers that they go for apple or google solutions?