The excuse I probably get the most from potential clients is that they're so busy. I don't believe them. I have no doubt these people have a lot of stuff to do. I just don't think they're that busy. I'll explain. Busy means you have extra stuff to do. If you do the same thing day after day, month after month, year after year then you can't call yourself busy. Yeah you may do a lot everyday but that doesn't make you busy.
I don't consider it busy because busy doesn't last forever. Busy is temporary. Going to work everyday and taking care of your family and social responsibilities does not make you busy. Unless you can afford to quit your job or you can/want to get rid of your family, then this is your life.
This is where busy becomes an excuse. This is how it usually works: I say, "would you like to [insert thing you don't like]?" You reply, "Sorry, I can't. I'm really busy right now." On the other hand I say, "would you like to [insert thing you do like]?" You reply, "totally, let me make some arrangements but I'm in."
The only variable that changed is your desire. You still have work and other responsibilities. When desire is high enough, how busy you are becomes irrelevant. All of a sudden all the stuff you had to do, doesn't have to get done anymore.
So the next time you find yourself about to "I'm too busy" ask yourself the following questions: do I have anything out of the ordinary to do? If yes, you might be busy. If no, ask is the real reason just because I don't want to? The answer to this question will probably be no you don't.