Created attachment 106544 [details]
How different fonts look like with 'Bold'.
See Image. The boldening only looks strange in OS X, with serif fonts.
Steps to reproduce:
1. Try using a serif font, make it bolder.
2. If this isn't really significant, try using something CJK, e.g. copypasta from Wikipedia.
THIS ALSO OCCURS IN LIBREOFFICE IMPRESS, AND SO ON.
Operating System: Mac OS X
Version: 220.127.116.11 release
Btw, this only happens in the UI. Printing and PDF exporting is not affected.
Those fonts (but Source Han Sans) don't have a real "bold" style, so the rendering system fakes the bold style, but it's adding too much weight to it.
*** This bug has been marked as a duplicate of bug 71034 ***