Which conditions can cause non ideal gas behavior by 1) decreasing the space between gas particles or 2) by slowing gas particles so that interactions are significant?

The condition that can cause non ideal gas behavior by decreasing the space between gas particles so that interactions are significant would be high pressure. Subjecting a system of gas with high pressure, would decrease the volume of the system thus making the molecules closer to each other. With this, we cannot neglect the interactions of the molecules. For the other case, the condition that can cause non ideal gas behavior by slowing gas particles so that interactions are significant would be low temperature. Lowering the temperature, would decrease the average kinetic energy of the molecules this decreasing the speed of the molecules making the interactions much more significant.