The not so assertive Rachel..

So the dormant miser side of me is slowly gnawing its way out recently.. It is not that I tend to do so but recently I found myself struggling trying to get back what others owe me. I just do not know how to ask them for my money back.. Boo on me right?
To be honest I always have issues in being assertive. I just cannot say NO when my friends ask me for a favor...