Have you ever had a taste in your mouth that was left over or, more accurately, arrived there sometime after you finished eating or drinking whatever it was that produced that taste? That’s an aftertaste.
People typically don’t refer to aftertastes unless they’re foul or bitter. Why is that? Are we negative by nature? Are we looking for sympathy? Don’t we like taking the good with the bad? Who knows? Who cares?
The word aftertaste can be used rhetorically, rather than literally. You can, for example, talk about the bitter aftertaste of the latest round of office politics.
You can talk about it, but I can’t. I’ve been self-employed for more than two decades. I’ve only occasionally contracted outside help during. I’ve never had a full-time employee other than myself. If I talk about the bitter aftertaste of the office politics in my company I need professional mental help.
I don’t talk about my company’s office politics. However, that doesn’t negate the likelihood that I need professional mental help. But that’s another story.