Personality traits are a way to mechanise a character's personality. Ultimately, this should be roleplayed, but there are situations where it is useful to check whether a character can resist their base impulses. Providing a personality trait for characters means that players who want to play a character in a particular way can get more control over how their character behaves.

For this reason, personality traits are used as 'saving throws' against conditions, and they are always a measure of how well a character resists certain behaviours. Success in a trait check means that the character may behave as the player desires, failure means they behave as the GM rules. For example, the Bravery passion allows a character to resist fear, and stand their ground in the face of danger.

Traits aren't common in all genres and settings for YAGS, and their number and details may well vary between settings that they appear in.