But what do you do plan to do if everything is vetoed by someone?
Indeed; the problem with running on 100% consensus is that while it tolerates disagreement, it requires rational individuals capable of flexibility and dealing with not getting their way.
When you have one fanatic joining the argument, then only one outcome can possibly give 100% consensus; the fanatic gets what they want.
When two fanatics who disagree with each other join the argument, then consensus (as-defined-above) is impossible.
One can then suggest a concept of 'rough consensus' which is how this place generally works. Things get done if a very small number of people contest, IF the majority thinks that their objections are unreasonable. This overcomes the 'solitary fanatics' problem, but introduces the problem that the community gets to decide whose opinion doesn't count. The good thing about 'rough consensus' is that only a very small proportion of involved parties can be so excluded, or it becomes obvious that this is no longer 'rough consensus' but 'majority rule'.
-Matt (User:Morven)