"In the traditional vows, the institution — marriage — makes and forms the couple; the vows set out what marriage is and what it requires. In today's write-your-own or instant-download vows, the couple picks and chooses the promises they make to each other — they make their own definition. The more casual attitudes toward the vows are probably a symptom of our more casual attitude toward marriage."
I don't know about all that. What I don't like about couples writing their own vows is that the writing is probably going to be bad. Attention is drawn away from the awesome reality of vow-taking to the particular words these 2 characters thought were so profound. You have to think about how the vows compare to the traditional vows and, before you know it, you've gone all judgmental and then you feel like you're doubting the quality of the couple's relationship and that seems pretty shabby of you.