When I was younger (still do it to an extent sometimes), I'd find myself suddenly passionate for the same hobbies/movies/music/food/etc as my boyfriend/friends/family. Especially when I missed them. It is possibly, partly due to the fact that I was still in the process of developing my sense of identity. But I think a lot of it was because I came to associate all these things with the people I loved and I was so moved by them... this was kind of my slightly twisted way of loving them and remembering them.
Example, I became best friends with a girl I lived with 3 years ago. She loved eating Kinder Bueno bars. I thought they were nice enough but I never understood her obsession with them. I also despised leopard print, hot pink and many of her other great loves. When she graduated and moved back home to Swindon, I found myself drawn to all these things, felt a little warmer and more hopeful whenever I hate Bueno bars. It felt nostalgic. So before I knew it, I found myself constantly buying them. I think this was my weird way of missing her lol like cherishing and trying to grasp at little bits of her personality and keeping her here with me. Cause I love my people for everything they are and I miss them terribly when they go away. I'm highly independent so I keep it to myself but these little things are like my 'I miss you' symptoms.