[CoUHKT57BSe]

You can also add 3D View to the list, that was so handy. Funny that Mozilla killed it and inspired MS and now it's in Edge :-D

[kroltan]

3D View taught me that Bootstrap layouts are maniac and ridiculously convoluted, with layouts deeper than they are wide on default settings.

To this day I always try to keep the element tree as shallow as possible (turns out this also has performance benefits in most cases)