I'm guilty of using the phrase "To a certain extent" all the time. I say "guilty"
because I think that I almost never mean it when I use it.
Think about it in context:
I think it's OK to wrestle pigeons to the ground and then chew on their feet without
their express, written consent - To a certain extent, anyway.
When you say "To a certain extent," it's kind of implied that you have a well defined
set of boundaries in your head beyond which you would not pass while engaging in a
particular activity. However, if called upon to articulate these boundaries, most
of us would fail to produce anything.
Just something to think about. You're all guilty, too, you know.