How much goofing off is acceptable in the work place?

Everyone goofs off a little bit in the work place, especially when there is access to the Internet. However, most professionally-minded people try to keep the ratio of work-time to goof-off-time in favor of productive work.

Enter my office mate, V. V is very young. This is her first full time job out of college. When you ask V to do something, she takes on the task without complaint and usually delivers great results in a timely fashion. However, without direction V is easily distracted and prone to massive amounts of goof-off-time.

I appreciate that she is young. I also appreciate that she usually meets requests in a timely fashion, and sometimes offers up solutions to issues that no one else considered. That said, last week V nearly became a stain on our office carpet.

V is habitually late since she doesn't have a car and must rely on public transportation. She also doesn't make up the time at the end of the day, because she needs to work around the schedule of said public transportation. She is basically in the building for just over eight hours most days, but thinks nothing of taking an hour for lunch.

Last week, V decided that she was tired of being a slave to public transportation and began shopping for a car. Her enthusiasm for this endeavor amounted to her utilizing most of the work day on both Thursday and Friday in pursuit of a vehicle. I tried not to let this bother me too much, since ultimately her new car would eliminate her excuse for working abbreviated days as a slave to public transportation.

However, since V has never had to purchase a car on her own and there were so many ins-and-outs involved in the purchase of the car, she felt the need to constantly interrupt me both days to ask for my input, opinion, and advice. She was even late to (and poorly prepared for) a meeting because she was busy showing car pictures to a friend from another group. I even tried to point out that she was going to be late and that she needed to read through a document before the meeting.

Friday afternoon, the two of us got out of a meeting around 4:30. I needed to write up the notes from the meeting before leaving for a three day weekend, so I could go home. However, V picked right back up with her vehicle drama as soon as we got back to our office. It took every ounce of my will power not to scream at her to "Shut the F**k up so I can finish up and go home." As it was, I wasn't really able to finish up my notes until after she left to catch her bus.

She left that meeting with an action item, which she still hasn't begun as of COB today. I guess I will have to nudge her tomorrow.

While I am supposed to be acting as a 'mentor' of sorts to V, sometimes it is difficult. I am not her supervisor, and I am definitely not her mother. So, how does one tactfully encourage a peer to refocus their energies on actual work in the work place?