Understanding the purpose of the pre-surgery diet helps to cement its importance in your head.
Visualizing my surgeon trying to lift my too heavy "unshrunk" liver and possibly not being able to do his job properly, was enough to convince me to not cheat. Also, and I'm not sure how often this happens, but imagine being told that your surgery had to be rescheduled because you didn't follow the diet? Then... you'd have to start the diet all over again for your new surgery date, and you wouldn't get any credit for the six days you've already invested up to this point. More co-pays might apply as well. Plus, hospitals don't just write-off a failed surgery attempt.
I should also disclose that my pre-surgery diet was only for one week, not two, so I feel a little awkward "lecturing" you about this. What do I know?!