The way the conditional formatting rules are currently written:
1. You can create condtions that are X or Y when X and Y are values that have already been filled in by click on both from the menu.
2. You can create chains of "and" statements based on various condtions such as "is blank" or "greater than" both when you elect to "define custom criteria" and by clicking "add condition (AND)"
However, you cannot do so for "or." Forcing the workaround of creating a new rule for each "or"
Not only is this time consuming for setup, it also makes the rules list an unweildy nightmare.
Currently I a managing a massive spreadsheet where I use conditional formatting to improve accuracy by highlighting cells with perplexing results. The rules list is already too unweildy, without having to create two rules every time I want: N/A or "is blank"