Tonal systems have hierarchical structure. The most stable tone is the tonic (if you are playing over a G chord a G note wil sound good). The other stable tones are 3 and 5 (B and D in the key of G major). So in terms of what notes will sond good over a G major chord G is the best, then D, then B. All three are stable in that they sound finished and resolved, so if you are going to end a lick or line over a G major chord these three will sound the best.
All other tones are unstable and will naturally want to resolve to one of the stable tones. Unstable tones generally resolve downwards: 2 (A) resloves to 1 (G), 4 ( C ) resloves to 3 ( B ), 6 (E) resloves to 5 (D). However the most unstable diatonic tone, 7 (Fsharp), resolves up to 1 (G). These are the natural resolutions for the G major (Ionian) scale.
What I meant in my previous post is that is you treat all the modes as being the same as the parent major scale you will resolve to the wrong notes.