Exactly. 

Terribly sorry but I beg to differ, The past is just that, memories.

-Just because you (think) you remember something there's nothing to say that it couldn't have been implanted by, let's call it "Higher beings/powers".

-The only thing you can experience is the "now" which doesn't really exist for us either as we, as stated, perceive time as constantly moving forward (just to make this thing about time a little bit more F'd up)

Time is what many people waist, always thinking they will do it tomorrow. Should have done it when they thought about doing it.

Time is when people wonder "where did the time go" It moved forward as it always does and you did nothing about using it. Time decided not to wait till you decided to use it correctly or exactly how you wanted to use it.

We do projects and something went wrong and we have to start over again. One may say "what a waist of time" No it wasn't because something was learned so we wouldn't do it wrong again next time. No time is wasted when learning things.

We do things we like, enjoy, or even projects or work. Things get done and we wonder where that time went. Time went forward as it should but we made good use of it.

Use time wisely because as soon as I hit "Post Reply" I may not be here anymore to know what time is doing for me.

Let's say you are in an infinite perfect vacuum and your space ship is the
only thing in the vacuum.
Now you turn on your engines and accelerate,
what are you moving through?
I thought about this a lot and I think
the only thing you are moving through is time.

The space/time continuum or just space/time. And, believe it or not, there's no such thing as empty space or a perfect vacuum, zero point energy has been observed. Plus you can move through a medium (water...air...space) but not through a man made concept. 

It would be like 'surfing' through the time zones. In this case it would be time lines rather than zones. Instances of time in an infinite variety. Choose your path very carefully. Getting lost in time would not be fun.