If you're a recovering alcoholic, it can be easy to talk yourself into one drink (or two) with friends at bar one night.

If you're self-employed, you have the luxury of being able to take an afternoon off during a workday to go hang out on the beach, if you so choose.

If you resolve to save money by brewing your coffee at home and taking it to work, it can be easy to skip it one morning and pay the $2 at Starbucks for your coffee instead.

The problem with making these kinds of exceptions is that we're creatures of habit. If you do something once, it's all that much easier to do it the next time, and even easier the time after that, and so on. It's very easy for these one-time acts to become recurring ones.

Where can you use this to your advantage? In overcoming fear, I think. Last night, I went hiking by myself in the mountains well after dusk, into woods that are crawling with scorpions (which give me the heebie jeebies, but probably shouldn't) and rattlesnakes (which don't give me the heebie jeebies, but probably ought to.) There was a real palpable fear that grew the deeper into the woods I went, which took the form of a lump in my throat.

But I pressed through it and managed to make it all the way to the top. Wasn't easy, but I did it. And now that I've done it once, it will (hopefully) be easier next time.

Stay away from those bad exceptions. And push through the ones you stand to benefit from.