How can I hide some columns in a QGIS table while I am working on it so that I don't need to scroll so far to the left or right when I have a large number of attributes? Something like Excel does for spreadsheets.
For QGIS 3 the same process is a little bit different. Setup of columns visibility should be done in Layer properties - Attributes form. The explicit manual is here.
Using QGIS 2.14, please select your layer and right-click your mouse, open Properties. On Layer Properties window, push Text Edit button of your target field, under Edit Widget.
By selecting Hidden, your column will be invisible.
NOTE: Please do not Hide your column if you are using other Widget function, such as Value Map. When you set "Hidden", your Value Map setting will be erased...