Haha, I picked the Expert Dreamer one before I realized that there was a badge for Streetpass. I'd change my vote if I could though, since I got the game rather late (late spring this year) and have Streetpassed 0 people xP.
i voted for street pass but then i remembered that even though i restarted my town last month i already have bronze. leaving the house finally paid off! xD gold medalist is going to be so tedious D:
I voted for the expert streetpass badge as well. I did get the bronze in under a year of actually trying, but I went out of my way several times like walking back and forth hoping to collect some tags. For actually playing the game, gold medalist badge is a tedious process. It took a long time and had to set aside little goals plus keep track of how many medals I spent to avoid playing more than necessary.
I've never streetpassed before because the 3ds (and nintendo in general) isn't exactly hot stuff here.