@MissCourt - I see what you mean by cookie-cutter houses -- residential area in particular are awful about making every single house look the same! I guess it must be easier on the builders or something.
I think the main reason that most building look the same is because everything has to be built in mass quantity and as quickly as possible in order for the owners to make a profit.
If you think Mayan lintels are nice, you should look into Buddhist lintels. The designs are amazing! It must have taken months to make each lintel. To think it was all made by hand -- no complex chiseling tools or nothing.