1) Commitment was questioned -- in my case, I disappeared for a rainy weekend for my wife's birthday and wasn't online over the weekend.
2) Attitude was questioned -- regular beat the staff meetings in the morning after pulling an all nighter, I tossed the pen to the next guy (a friend) and miss threw and it hit the ceiling. "Why are you being an asshole?" It took a bit to realize that was what was being asked.
3) After a great showing at Demo we launched with no ops/support and engineers with the knowledge (me) were expected to be on call after 80 hour weeks. I got grumbled at due to a support issue as I was returning from a morning at the Legion of Honor and heading down Highway 1 (no signal, peace). Oh, the wife wasn't happy either -- "why are they bugging you on a Saturday morning?"
That said, the overall product we built was one of the more fun and diverse I was involved in. It was very hard to make the decision, but sometimes you know it is just right to walk away.
There are startups that are like that. Sometimes, like the post above, the signs are there early. Sometimes, they don't show themselves until much later.
A couple of years later when the company had an exit, of the 35+ people that were there when I left, only four that I new (including the two founders) actually remained.
Assuming it was a good exit, those 2 are some shrewd (and despicable) founders.
It was a learning experience for me -- specifically, not to get lost in the interest of solving problems at the expense of personal work/life balance.
We all have our faults, professionally, you hopefully learn what those are and not repeat them.
Defamation lawsuits are expensive to launch or defend; but a vengeful founder usually has more money that an individual.
if you're a scared american, anonymity still works on the internet. for now.