Make the right precautions
I would urge all businesses to draft a shareholder’s agreement when everyone is amicable.
Work through the potential stress point early, identify roles at the outset and agree what needs to happen if agreement cannot be reached. Make these decisions as partners, or even friends, and it’ll help you to look forward and visualise how you may deal with things if or when they come up.
The sign of a perfect shareholders agreement is when it gets drafted (argued about and sulked over) and then put in a drawer and never looked at again. If it’s done when a conflict has already arisen, it’s often too late.