There is a very simple way to improve the appearance of fonts in many of your favorite Ubunt.
To do this, just create one file: ~ / .fonts.conf
And put in it the following:
<?xml version="1.0"?>
<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
<fontconfig>
<match target="font">
<edit name="autohint" mode="assign">
<bool>true</bool>
</edit>
</match>
</fontconfig>
Next, do logout.
Go to System (system) -> Preferences (settings) -> Appearance (appearance)
We get to the Fonts tab (fonts)
Determined to click Advanced (optional)
And we play with the settings to your taste without forgetting to choose Subpixel smoothing (subpixel smoothing)
And enjoy, of course.
')
At the request of
nblxa I attach a screenshot:
before:

after:

PS I strongly recommend everyone to look
at the iZENfire comment , after these actions the last shortcomings disappeared.