This has nothing to do with how, why or when Spirit chooses to visit. Most "ghosts" are not strangers. They are loved ones, like your friend, who often reach out in strange and funny ways to say hello at important times--anniversaries of death, birthdays ,etc.
It's commonplace in my life. I've written about my own and others' experience here.
I totally agree that sensitive people, who often deal with depression, anxiety and addiction, essily pick up energy from other sources. That's why we suffer from addiction and depression. It's our curse and super power.
Did your friend have a sense of humor? Feels like she might have had a liitle fun with you.
Thanks for sharing your story.