i think if you are aiming to play something
like an A chord, you had better not hit the D note
if you do [music theory] it instantly either
sounds like A-sus4, which is a very weird chord,
or it sounds like you are playing [part of the]
D chord, which does NOT sound right if everyone
else is playing A
adding the G note to a partial F chord
[AFG] is going to sound weird too
it suggests an F9, which has its place in
some music, but not really in anything like
cajun or zydeco
what you need is a book called 'chord chemistry'
which tells how to make different chords and
what they are usually used for
you can try anything you want, though, it might work
what will stick out though, if you just
do one weird chord, is the fact that it;s the only one
usually guitar and keyboard players throw in
9ths, 2nds, suspendeds, but they have the ability
to do it all the time, you will only have
limited opportunities on the one row
and they are not usually playing simple folk music
when they are doing that