It's all in our minds that time seems to slow down when waiting for something.
When we're waiting for something we're focusing on the time that is passing by and watching the clock and/or calendar so when we focus on the time it makes our minds think that the time is dragging by.
If we keep busy doing something and focusing on other things we don't notice the time passing by so it seems that the time has sped up and now the event or other thing you're waiting on is here.
Like say you're waiting for a Birthday to come and the time is dragging but when the birthday gets here and you're having the party and having fun at the birthday party then the time seems to pass fast because you're having fun and not focusing on the time.
If you're waiting on a package to arrive or another event to arrive then to make time seem to speed up go do something else to keep your mind off the time and before you know it the time will be here and your event or package will arrive.
I know the feeling when I order something online and the time seems to drag when I track the package to see where it is and it seems to take forever for it to get here.
Like right now I ordered a brand new computer to replace my current 5 year old desktop computer that I'm using now and I can't wait until the computer gets here so I can set it up and start using it.
It's supposed to be here in 2 more days but that seems like a long way off but in reality it isn't.