Inspired by this question.
The spell Friends specifically states that an affected creature is aware that it was magicked:
When the spell ends, the creature realizes that you used magic to influence its mood...
Charm Person has a similar clause.
However, other spells (such as Suggestion) do not. Does a creature affected by Suggestion (or another enchantment without an awareness clause) ever become aware that it was magicked into giving away that warhorse?
Related: Is a character (player or otherwise) aware that it made a saving throw against a non-obvious threat? If Wegris the Barbarian Dexterity-saves against a fireball, he knows it. Can he tell someone tried to scan his mind with Detect Thoughts? Does it make a difference if the save is successful or not?