Ubuntu – Why does LibreOffice look old

You have the tango icon theme selected (this not a legacy Open-Office theme by the way). Also I found that LibreOffice seems to force certain themes if your GTK+ theme is changed (at least in 3.4, so they might have back ported that to 3.3.3).

What you can do is go to tools>options>view and choose another theme (such as galaxy). If you don't have that theme, then you need to install the other LibreOffice icon themes (called styles) from the Software Centre or synaptic.

By investigating with Synaptic and trial & error method I came up with the solution:

sudo apt-get install libreoffice-style-tango libreoffice-gtk libreoffice-gtk3

I have no idea why these packages were missing. I hope this helps someone.