> Whenever you normally use some programs with other options than their defaults, it is simpler to define aliases for those programs.

I don't buy into this. These aliases tend to come at the cost, or at least the risk, that your workflow breaks when you are at another computer or working on a shell on some server that doesn't have this alias. That's why I like additional aliases, like l for ls, but with your favorite options. But I dislike aliases that change default behavior - and often in an intransparent way.