There are two emotions that you can control to prevent burnout and increase the likelihood of success: excitement and empathy.
Empathy is for your customer and for the problem you are trying to solve. Intimately knowing the problem or the customer you are trying to serve helps remove some of the startup risk, minimizes the time to market and cost before you even begin. Be your first customer.
Excitement is for the psychology of you and your team and to create an environment that obsesses over detail. Genuine excitement from the team fosters this type of detail. It comes from the labor of love.
If I had to give another name to burnout it would be heartless ambition. Personified: Work ethic and drive focused on the ends and not the means.
In a famous lecture called The Five Cognitive Distortions of People Who Get Stuff Done Stanford Professor, Michael Deering, refers to a distortion called Schumpeterianism named after the famous Austrian economist and one of the earliest contributors to the subject of entrepreneurship. Schumpeterianism refers to those that feel as though disruption and creative destruction is their vocation. Their internal thoughts resemble, "I am a creative destruction machine." Schumpeter believed that these individuals were the drivers of a prosperous economy and that creative destruction was what powers capitalism.
Heartless ambition is motivation for the ends and not the means. Burnout happens when the fumes of ambition alone run out and there's no synapse between the work and meaning.
You are the only authority on what is exciting to you. Excitement prevails even when there's lack of momentum, droughts of positive feedback, and when everything else seems like it caught on fire. Excitement still happens when and where heartless ambition meets the end of the road, excitement for you and your team will always keep you on the train.
Beyond personal excitement for your well being and the team, excitement and love for what you're working on in the moment is where obsession to detail is derived. This is where referrals and evangelists of your product come from.
Your customers will positively promote products they love to other people only when the experience has exceeded expectations. You cannot expect to create an experience that exceeds expectations if you are not in love with the details. And you cannot expect to have a prosperous company if you don't have evangelists that get you new customers. It's harder to get a customer than it is to build a product.
Be your first customer. Being passionate enough about what you're working on to care about knowing the problem well enough. Empathy for your customer is a means and not an end. It's a love for being a part of a solution.
Andrew Mason's note to Groupon when he was fired was: "If there's one piece of wisdom that this simple pilgrim would like to impart upon you: have the courage to start with the customer. My biggest regrets are the moments that I let a lack of data override my intuition on what's best for our customers. This leadership change gives you some breathing room to break bad habits and deliver sustainable customer happiness—don't waste the opportunity!"
It's not just important enough to understand the problem. You have to love the problem and want to know more about it every opportunity you have. You have to go out of your way to hear bad feedback. Bad feedback is the only actionable feedback there is. When someone tells us, "I love your product" there is nothing to do. When someone says, "you suck" we can ask them why. It's usually one thing that is giving them problems and which we can act on. Consistently seeking this type of feedback could drive anyone crazy when you need to do it for years if you don't love the customer and the problem.
In any facet of life, we find ourselves in situations we don't want to be in when we're focused on the ends and not the means. I have no way of telling if the students I'm talking to are genuinely passionate or excited about what they are working on or if they are just doing it because they want to make money or they want to be recognized. Because of that I ask them to imagine what their dream job would be for a second. Then ask them to consider that job as what I'd like them to use this content for. If they are already doing their dream job then I believe they've controlled for the biggest threats to their success and the overlooked emotions necessary: empathy and excitement.
Life is short. Do something you love. Do it with people you love working with and be your own first customer.