I've never done anything much with the default sims, since I'd rather make my own sims and wreck havoc on their lives instead :'D
Let's see, I've really only played the Veronaville Sims, soo; Juliette realized that she was too good for Romeo, and instead, ran off with another sim teen of mine (a much cuter one, teehee). I don't have pictures though, they made gorgeous red headed kids :c
A rich sim of mine was interested in the Broke family, but they made enemies instead for some reason.
The Summerdream family, I had my fun with; they were very hostile to the Sims I made (rather than, oh, say, the townies), I took revenge and burnt them all in a horrible, fire-related accident
My Sims no longer live in a neighborhood full of mean thespians and can now go around making friends \o/ YAY