Kato was claustrophobic and had to cast Remove Fear on herself (prayed for Shaundakul to make her brave) whenever her ventures took her below ground or into any cave. When the spell ran out though she wasnt of much use.
After being set on fire more than once by CoG gnomes, she developed a fear of gnomes as well - one in particular - and would panic whenever one was near, and reaching for a wand of endure elements.
Not sure if this is the kind of stuff the DMs are looking for, but it's what worked for that particular character.