Conflicted with big stacks - NLCASH

[MasterLJ]

Let's say you are crushing your opponent. You now have 4 buy-ins on the table and they keep rebuying for full buy-ins.

Why would we risk our stack against them continuing to play? Would it be optimal to quit them and fire up another game with them at a different table? Is it optimal to keep playing with a large amount of buy-ins on the table? If not, at what point would you quit?

I feel that opponent's aggression comes into play here. The more aggressive they are the less motivated I am to continue playing with a deepstack since I'm pushing in much more marginal spots.