Your example does not sound too odd to me. On the contrary usually means "as an opposite," but people often use it to mean "differently." I don't think that nodding is the opposite of cheek-kissing.
Tony kissed the girls. On the contrary, Ahmed turned his back on them.
I would find the following to sound odd:
I like sports. On the contrary, my wife likes music.
There is nothing contrary about sports and music. A contrary relationship would be:
I like sports. On the contrary, my wife absolutely hates sports.
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