Ignoring balance what type interactions make logical sense to you? What current interactions don't make sense to you?

>Bugs should weak to poison
You spray bugs with poison to kill them.
>Bugs should be weak to electricity
Bugzappers.
>Grass should be weak to poison
You kill all sorts of weeds and other invasive plant life with poison sprays.
>Dragon should be weak to steel
Knights killed dragons with swords.
>Dark should be weak to fire
Fire makes light, removing the dark.
>Fairy should be weak to bug
Girls HATE bugs.
>Fairy should be weak to normal
42% suicide rate.

One of the only interactions that don't make sense to me is why fairy is strong against fighting. I would think tough guys would beat up girly people. Unless it's the idea of guys can't hit girls. If that is the case I would perfer fairy to be immune to fighting.