Why greek characters and symbols look crappy?
The tk/tcl libraries tries to find the best match for the fonts requested. Sometimes if font-sets are missing the unicode characters can be non-consistent with the other fonts. One easy way to fix this is to install extra fonts or change the font settings from the configuration dialog. A nice set of fonts are the Microsoft TrueType core fonts which can be freally downloaded and installed on linux. The RPM file and information can be found on the following site.