At some point in the past, while we were dating, I had my wife's phone and changed my contact name to something far more risqué than "Hot Wife". I called her, she saw it come up, we laughed, she changed it back a few days later.
My primary email address was . But somehow this name got associated with . Google notoriously ignores dots in your email address most of the time, but apparently not all of the time. Google Contacts does all sorts of magic when merging multiple contacts as one. Structurally my wife had two contacts for me with different email addresses, but the UI was merging them into a single display contact. Since we used the form with the dot in it, nobody noticed....
... until about 10 years later. We were now married, had kids, and we're in the process of interviewing to hire an au pair (a live-in, foreign exchange nanny). My wife emailed a prospective au pair, the agency, and CCed me, but fat fingered the email address without the dot.
We were dropped by the au pair agency and had to go with a different one.