I have come to believe the same.
Plus I have seen really complex and unfruitful css when a project starts customizing and extending ie Bootstrap.
Plus I have seen really complex and unfruitful css when a project starts customizing and extending ie Bootstrap.
The defaults are pretty sensible, so as long as everyone - including the designers - understand they need to customise the design to Bootstrap rather than Bootstrap to the designs it works really well.
It' a fast way of working as Bootstrap has already done most of the basic stuff, and by making changes in the right places it's easily possible to not make it look like 'just another Bootstrap site'.