Understanding comparison using Big O notation
I was going through this [heavily discussed and highly voted question on SO][1] and stumbled across one [commnent][2] that got 5 upvotes . So I assume this was a great comment .But it got my head spinning at the same time . Can any one explain this comment ? The comment says :

> You can't compare big-O values directly without thinking about constant factors. For small lists (and most lists are small), ArrayList's O(N) is faster than LinkedList's O(1).

[1]:http://stackoverflow.com/questions/322715/when-to-use-linkedlist-over-arraylist
[2]:http://stackoverflow.com/questions/322715/when-to-use-linkedlist-over-arraylist/322742#comment3883863_2603253 
Understanding comparison using Big O notation
===

I was going through this [heavily discussed and highly voted question on SO][1] and stumbled across one [commnent][2] that got 5 upvotes . So I assume this was a great comment .But it got my head spinning at the same time . Can any one explain this comment ? The comment says :

> You can't compare big-O values directly without thinking about constant factors. For small lists (and most lists are small), ArrayList's O(N) is faster than LinkedList's O(1).

[1]:http://stackoverflow.com/questions/322715/when-to-use-linkedlist-over-arraylist
[2]:http://stackoverflow.com/questions/322715/when-to-use-linkedlist-over-arraylist/322742#comment3883863_2603253 