Comfort equals death.
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One of the big challenges to our willpower is knowing that whatever change we're trying to make is going to involve some discomfort, and we all naturally avoid it. But there's value in being uncomfortable. It's a little bit like getting a massage. The more pain you can endure, the greater the benefit. When it comes to exercise, you're going to be sore. There's just no way around it. And so when you wake up, and you're sore, and you don't want to work out, that's the crucial time to do it. And you won't regret it. You should never regret it.