What is your spending Achilles Heel?

When it comes to money management we can be our own worst enemy. Even when we've made an effort to budget carefully, there are times when things go awry, we overspend dramatically, and we end up borrowing money for everyday expenses at the end of the month. Some of the things we overspend on are unavoidable expenses out of the blue, but sometimes we have simply fallen victim to our spending Achilles Heel.

So what's your spending weakness, and how can you protect yourself against it?