This familiarity isn't a bad thing. It's called a "comfort zone" for a reason. The critical requirement lies in not allowing yourself to get lazy. You mustn't fall into the trap of thinking that this is all there is to your existence. The world contains so much more.
And so, if you find yourself slipping, here are a handful of little acts to pull you out of your routine:
1. Add a new artist to your Pandora station
The song lists seem pretty static - good for nostalgia, not so good for your horizons. Mix it up with something new.
2. Take an unconventional route to work
It may add a few extra minutes, but the experience of almost getting lost on your way to work is priceless. (This is experience talking.)
3. Make a decision with a randomizing device
Close your eyes and point to your lunch destination on a list of restaurants. Use a Magic 8 ball to X. Draw straws for household chores.
4. Try a new meal
It's a gamble. You may like it, or you may not, but at least you tried. It may become your next favorite.
5. Shop at a different store
Buy groceries at that little place down the street, rather than the big mega-mart (or if you typically go to the little place, try the mega-mart). Look for clothes in that hipster joint you've always passed by. Maybe even step into a comic book shop.
6. Look for entertainment (books/music/movies) in a new section or subject area
We tend to stick with our favorite categories. Live a little and explore.
7. Break your lunch routine
Take a walk. Eat at a different time of day. Do something that shakes things up.
8. Try an activity that you fear
Find something that you'd like to do, but are afraid, and do it anyway. Examples include dancing in a flash mob, getting on stage during open mic night, and talking to beautiful strangers.
A little chaos can be good. Sometimes, you need to shake things up. Please try one or all of these ideas. They will push your boundaries, but in safe and mostly comfortable ways. Challenge yourself, and you will see rewards. Most of all, enjoy. This life is yours, whatever you make of it.