While the concept of a Universal Accelerator is silly at best, your notions are far worse. If you lean far enough to a side, you will topple over, but you will remain stationary as long as you maintain balance. The reason this differs from a 'rocket house' is because if the house veers slightly, the rocket, and thus the direction of the force impulse, also changes, and that effect will become cumulative unless it is corrected. Now, if you mean, why don't we experience shaking? That would be the air colliding with the rocket. There is no turbulence in space. Well, at least not to the same degree.