[stylist] journal writing

[Vejas]

Hi all,
Have any of you ever had experience writing a fiction novel or 
short story in journal form? Is it easy to do?
I'm thinking of writing something using this form.  I've read a 
few books that are meant to be first-person journals and would 
really enjoy experimenting with this style.  My main question 
about fiction journal writing is: Does there have to be a theme, 
or can it just be the day-toDay life of someone over a period of 
time? I have kept my own journal for a year, where I put down 
many of my thoughts and feelings, and haven't really been able to 
find a main theme with them.  I just feel that peoples' 
day-to-day lives are often so complex, and each day is so 
different, that a theme would be hard to find.
I'd really appreciate input.
Thanks,
Vejas