Seeing if someone will fit into your culture can be a vague way of really seeing if you and your team will like them -- even if your company's culture is well defined. It's important for people to get along, but it might be more advantageous to ask how someone can add to your culture instead.
In its worst form, hiring for "culture fit" can equal looking for people who look, talk, and act like you. The "beer test". Would I like to have a beer with this person?
This way of thinking can also go hand in hand with casual, unstructured job interviews -- and as we recently mentioned, that casual job interview might not be doing you the favours you think it is.
Instead, concentrate on what a person could add to your culture. This is a diversity thing, but also kind of not what you'd think when normally hearing the word "diversity". It's about diversity of opinions as well, diversity of backgrounds, and diversity of experiences.
If your business is about creativity, imagine what all of those new experiences will bring. If your business is public facing, it's all the more important to avoid a tone-deafness when dealing with the public.
Ultimately, it's about making sure everyone remains challenged and exposed to new ideas, which has been proven to result in higher performing workplaces. Being comfortable sounds nice, but it's one step away from being complacent.