When getting a co-founder, employee, investor or any other stakeholder for your startup, one of the most important metrics you want to scan for is belief in the startup over and above any monetary compensation. Simon Sinek says it beautifully – “If you hire people just because they can do a job, they’ll work for your money. But if you hire people who believe what you believe, they’ll work for you with blood and sweat and tears.”

In any startup – things will go wrong, stuff will break, investors will pass, your product will suck, employees will quit, hiring will be a problem, deadlines will be pushed, users will not be engaged, partners will bail – but you and your team still need to keep pushing through.

You will face rejection over and over and over again – from investors, users, and pretty much everyone you talk to. You will hear people give several reasons why the startup will not work – but you and your team still need to keep pushing through.

Ben Silbermann, CEO of Pinterest said, “There are lots of ways for investors to say no to you, and I’m pretty sure I’ve heard every single one”

Elon Musk compared running a startup as “eating glass” and “staring into an abyss of death.“

The TechCrunch stories of “we got 100k users in 2 days” – all have a long grind where they failed over and over again before their overnight successes.

Instagram slogged through Burbn, Twitter slogged through Odeo, Foursquare slogged through a failed acquisition by Google, Rovio slogged through 51 games prior to Angry Birds, Starcraft was almost abandoned, SpaceX blew through $120m almost bankrupting Elon Musk with 3 failed rockets – but they all kept pushing through.

When things go bad, and they always do, you need people who work with you with “blood, sweat and tears.” Startups are never easy and only unreasonable obsession can power you through the grind. Make sure you have it.