Anko is a very straightforward, observant, and sociable woman with a primarily casual attitude who likes to mess around with others.
However, she can change her mood in the blink of an eye and quickly unsettle someone, either by becoming completely serious or displaying her unstable side. In the latter, it becomes apparent that she's got a few screws loose.
Anko has a goofy side that's shown on some occasions, like when she genuinely thinks that Kou wants to be in a relationship with her