You also have to note that the basic GUI introduced in Windows 95 was so successful that it has persisted until now in Windows versions up to 7, and will continue for the most part - with Windows Explorer unifying the desktop shell, file manager, and control panel functionality into a single fluid and customizable entity, blurring the differences between the individual component programs. Quite rapidly over the next 2 years, Internet Explorer was also closely integrated into Windows 95, and even the Microsoft Office Suite, so that you could almost seamlessly transform your view from the Explorer file manager to the IE Browser to multifunctional documents with Objects that were Linked and Embedded.
It was truly amazing, considering, as Mystere says, the constraints that small amounts of RAM and disk space put on systems that were partly 16- and partly 32-bit.
This led to rather cruel (and clever) epithets like:
"Windows 95 - a 32 bit extension and a graphical shell for a 16 bit patch to an 8 bit operating system originally coded for a 4 bit microprossessor, written by a 2 bit company that does'nt care 1 bit for its users."
One frustrating thing was that you could manually repair a broken Windows 3.1 system if you had the basic know-how - Windows 95 and successors became less and less accessible to the "mechanic" with more functionality obscured in the registry. You could manually fix a broken Windows 3.1 with sysedit, or if push came to shove, edlin!