Generally, should alignment be driving my character's actions, or should my character's actions be driving my alignment?
Sticking with the same example as in the previous question, my chaotic-neutral half-orc barbarian character flipped a boat of racist sailors who were making fun of his swimming. This was characterized as a "purely unmotivated evil act" by my DM, resulting in an alignment change to chaotic-evil.
Should I now be playing my character in a way that more accurately reflects my new evil alignment (eg by performing more evil actions than I normally would have when I was still chaotic neutral), or should I continue to play my character as I was before, and let the alignment change as it will based on my actions?
I ask since functionally, the alignment change was a surprise (you can read more about this in the previous question), and I am unsure how I am expected to act in light of this alignment change.
While to me alignment appears to be something which is determined by my chosen actions (and thus should not necessarily be driving my decisions in-game), given that alignment appears to have objective effects in game (eg it can be detected, class restrictions, etc) I could see the argument for alignment in some way driving my decisions. Similarly, having started my D&D career playing 3.5, I recall that alignment was extremely important, again lending credence to it in effect driving character action (though I am unsure if this is still the case in 5e).
This answer appears to be a start, but I am looking for something more directly relevant to game mechanics and expected social conventions than a DM perspective on how to force an alignment change. I am also not looking for how to determine if an action is consistent with an alignment or what it means to be "good" or "evil". Rather, I am interested in the effect alignment should have on player actions (if any at all).