As a layman I don't understand the 'problem' with time?

To me, time is relative to 'timers'. So how I perceive the world passing is a function of a electro/chemical activity in my head. I'd imagine if you could somehow 'double' this function I'd perceive time at half the speed. And I imagine if you were to turn off my 'timer' the world would pass by instantaneously.

I've heard that 'time' is the fourth dimension? But again, as a layman, I have to ask why isn't 'thought' the fourth dimension? Isn't it only by being conscious, by being a 'timer', that 'time' can even be perceived?