when you do that, you are holding the click for to long.
try this. go to the back button, click back but do it real quick (click and let go)
this will bring you back a page. now do the same thing but when you click hold it down, you will get the list pop up. you can then choose any site you have been to on that list. it will go away when you let go.
tap to click is a very useful feature where you can merely tap the pad and it will register a click rather than having to push down on the pad.
it was developed when trackpads were stationary and had buttons on the bottom to click. many people found it easier to tap the pad rather that going down to the button every time.
this is a prominent feature even in PC's i am surprised you have never come across this concept before.
lastly, you being a brand new convert to mac, i suggest that you go to the apple website and watch the tutorials that teach you the nuances of a mac.