I don't think it is very helpful to think of planets as (a) having difficulty expressing themselves, or (b) getting a free ride.
You can imagine a situation like Mars in Aries opposing Venus in Libra. Both planets will be strong because they are in the signs they rule (I. e., domiciled.)
So rather, think of opposing planets like two people who oppose one another's interests. They can see-saw between having one or the other dominate at different times, or they can develop a relationship where one person's interests are always subordinated to the dominant partner's; or they can develop a compromise that both parties can live with.
A key word for sextile is "excitement" because it involves the tension of the two-series with the flow of the three-series.
A trine is a powerful aspect, usually indicating a positive, constructive flow of energy between two planets. This isn't a "free ride," but a strong energy on its own.