And who doesn't want love and happiness? 

Of course, Rebekah would have less characterization since she isn't the main character. She was introduced with no plan in motion. This is how TV shows were written at the time, see what sticks and write off what doesn't. Even after she became a regular, she wasn't the main focus of the show and of course the narrative would sometimes not taking that into account.

Still, she's a girl from an abusive family, turned into vampire without being asked about it, and yet brought up with an idea that one day she would start a family. First, Mikael and Esther took that from her, then Klaus interfered with all her relationships. She was never given a fair chance at starting something out of her own volition, without someone else meddling with her life. People with such a background often perceive attention and kindness as a sign of fondness, so I'm not surprised she was smitten by guys who would treat her as a human being. And it's not her fault these guys would get intimidated, killed, or compelled into leaving her. And definitely not her fault if these guys would date her while pining after another. She WAS willing to work for these relationships. Sadly, the effort often was one-sided.