Conditional Formatting on Drop Down List

I'm not sure I understand what a trigger cell is. Let me define more clearly what I want so you can determine if your suggestion is appropriate. If it is, please provide more explination (I'm not an advanced Excel user). Thanks!!

1) i'm not sure what a trigger cell is
2) the "list" of options that the user can pick in the dropdown is hidden in cells AA6-AA21.
3) Some of those options are "good" and some are "bad.
4) What I'm tyring to accomplish is: if the user picks a "bad" option I want the entire row to turn yellow. If the user chooses a "good" option I want the row to remain without color.

By trigger cell I meant to say that in general, one would say some thing like this
if there is a data in cell in Column D, then turn that row red or if the value in cell C2 is yellow, then turn column C yellow. By trigger I meant the cell that will cause that event to occur.

Lets say that user will be picking up the values in column F based on the list defined in range AA6-AA21

so now you select the rows on which you want this change of color to occur. Lets say its whole sheet. In this case you select all rows

Now go to conditional formatting
and enter this formula

=OR($F1="bad value1", $F1="bad value2", $F1="bad value 3", "What a day")
and choose color yellow

Now if any cell in F column is "Bad Value1" or "bad value2" or "bad value 3", or "What a day" the whole row will turn yellow.
I Just had four values, but you can have more

Hope it make things better

How to do the same function as above for a range

@ABC, what you meant for a range. Color the range or being triggered by a range

Is there no way to get it to determine whether the value of the cell is one of the values in a defined list? It seems a shame to have to go to all that trouble to name the list so you can call it for use in a drop-down, but then not be able to use that call for formulae.

Only if you need more than three conditions or the formula cannot be written on sheet and needs some user defined function