I know I preface all my other you-are-stupid answers with this is a serious reply, but this time I mean it.
Friends are the easiest people to collection information from. Think about it. You’re always sharing information with each other- stories from your past, current likes/dislikes, plans for the future. Passwords are generally (read: always) made of personal information like names, years, and inside jokes. If you don’t have inside jokes and consider yourself friends, you aren’t really friends.
Friends are also very trusting. Has your friend ever used your computer? Have you ever used theirs? Both are great opportunities to either collect data or put something in place that will. Ever store a password on someone else’s computer out of habit? It happens alot. I wrote about it a long time ago
If you read that and follow the directions, you can get that EXTREMELY! important password without a lot of work. Best of luck ruining that friendship!