Chris Brogan is a regular favorite of mine and the web and recently posted a great guest article that takes 106 of the most common excuses and gives a couple words of encouragement / motivation / insight for each one.
I find the last few lines of the post particularly great for most situations and especially as you might be debating on whether to read it or not:
So what are you waiting for?
Overcome your obstacles, or make excuses; it’s as simple as that.
Check it out here: 106 Excuses That Prevent You From Ever Becoming Great.