I used to suffer from a lot of apathy, laziness, general lethargy, for working hard towards delayed gratification.
I have two ways of dealing with bouts of apathy when they arise. The first I wrote about in January, when I ask myself "how would I fail?" at something.
The second is a simple affirmation:
"If I am waiting to truly prefer to start something over all other activities, I'll be waiting forever."
Now sometimes I really do want to go to the gym. Maybe I ate a lot and feel a surge of energy or bloatedness; maybe I'm mad, or stressed, and need to release some energy.
But the daily grind required for a strong physique just isn't always appealing.
Now once I start exercising, I'm good to go. But my momentum of not exercising sometimes overpowers me and makes the change in direction of my day to start exercising difficult.
It's at these moments, that I remind myself that if I'm waiting until I want to start exercising over all other activities (including sitting on my ass on the couch), I may be waiting a long time.
Rather, my goal of the body I want, and the neurochemicals released after exercise, are more of a positive than the lethargy is a negative.
Don't want to take the plunge of working on a side-business? Maybe a touch of fear of failure, or just a general apathy at the hard work that's required? If you wait until you truly are going to prefer starting a project rather than sit around and enjoy a beer with friends, you may be waiting a long time. Your financial goals should be more powerful than your lethargy. Remind yourself that you are going to be waiting a long time to start something if you need to 100% prefer starting such a project over any other activity.
Tangentially, I used to have some minor approach anxiety at bars/clubs/that-starbucks-in-barnes-and-noble (you know, all the best spots for picking up quality girls). But if I stopped masturbating for a week, my lust would overpower my minor anxiety. If my brain knows that the only way it's going to release this built-up lustful pressure is to sleep with a girl, when I take the immediate release away from myself, that is going to be more powerful than any minor spell of approach anxiety.
Become self-aware as to what's truly the root of your apathy in different situations (start daily mindful meditation if you aren't self-aware enough yet, as long as you can overcome your apathy to start that!), and use psychological tricks on yourself to defeat it.