Maybe you need to think about what happens in real time.
When you start your car, the battery first provides voltage and current in the same direction. It provides output power to crank the engine. When the engine fires up, the alternator kicks in and the current flow (but not the battery voltage) is reversed to recharge the battery. The power flow also reverses. +Vx-I = -P Negative power with the power going back to the source if you see what I mean.
Alternating current, ac, as you know, is a sine wave. It alternates between positive and negative.
For a power factor of 1.0, both the current and voltage go positive and negative at exactly the same time. Power always flows from the supply to the load. Like the battery cranking the engine.
When the PF isn't 1.00 the current and voltage don't go positive and negative at the same time. There are periods where the voltage is positive and the current negative. The power flow is reversed and goes from load to supply. Like the alternator charging the battery.
Heres a picture of around 0.7 pf.
Mostly the power is positive but sometimes it is negative.
The current lags behind the voltage.
This is what happens in an inductive circuit - typically motors but nearly anything that has a wound coil.
When you apply voltage to that, it takes time for the current to rise. It also takes time for the current to fall. That's why the currents lags the voltage.
It's a bit like putting effort into getting a flywheel moving. It takes time to accelerate it. And time to stop it.
