"Personality, chemistry etc are everything. I think these are readily fleshed out in a weekend though. "
If you met a girl/guy and had one awesome weekend - would you believe you've figured each other out enough to commit to marriage?People are complex. Walking in with optimism is great but with a blind-eye to respecting the complexity of human nature may be unwise. In every social dynamic there are storming stages and if the relationships aren't strong you simply won't survive the storm. Or at least, most probably won't.
The next step seems clear to me though. Keep communication levels within your team high and find customers. Avoid the rocks and keep your eye on the prize. Welcome to the fray.