Tolerance of Dissonance
One of the strongest factors in music is the duality between tension and resolution, which can be found in the smallest musical units (e.g. V-I cadence) to the largest extents (big structure of symphonies etc.). However the ear of the 21st century listener is way more tolerant to dissonance than just a few decades ago which also reflects in the literature on composition.
This can be a source for confusion for learning composers. Traditional literature on composition has a very different understanding of dissonance than what we actually have nowadays (and what is used in film music). For our ear, it is no problem to accept a chord with a major seventh (e.g. Cmaj7) as a stable chord that doesn’t neccessarily want to resolve while for traditional understanding, the maj7 is a massively dissonant interval that can hardly be left alone without a proper resolution.
In this regard following the rules learned from books versus what can actually be observed in current music can be quite contrary. The only interval that we still find massively dissonant is the minor ninth (which create a stronger dissonance than the minor second which consists of the same notes). All other intervals can be part of chords that don’t neccessarily need a resolution. A quite extreme example for our tolerance for dissonance is a lydian chord (e.g. Cmaj7/9/#11) where we find major7, major 9 and a tritone as part of the chord structure and yet, it doesn’t have the massive urgency to resolve for most of today’s listeners ears.
Keep that in mind when you study composition and when you once again are confused by classical music theory versus current reality.