I really wish that the default value for the GridLines property on the DataGrid (and possibly Repeater/DataList) was set to "None" and not "Both". I mean, I can see the reason for having this if someone wanted to just plop some data on a webpage, and didn't care about formatting or defining their own columns. But, for about 99% of the time, developers have to build the Columns manually, set styles, etc. etc. until it looks the way we want it. I've never seen a DG in production that has GridLines, mainly because it just looks plain stupid with custom formatting.
So, why do we have to write GridLines="None" every time we build a DataGrid just to suffice that 1% of users that don't give a crap about formatting or are just showing the powerful use of the DG without writing a bunch of code? ARRH!