The phrase often suggests a playful or less serious interest, rather than deep fascination. A whimsical hat display in the store window tickled her fancy.
Pro Tip 2/3
Personal Appeal
Use it to express personal interest or pleasure, indicating something is especially appealing to you. Vintage cars really tickle his fancy.
Pro Tip 3/3
Subjective Taste
What tickles someone's fancy might not interest others, showing subjectivity in preferences. I'm not sure if opera will tickle your fancy, but it's worth a try!