Commonly I think it is actually "please me to no end" (at least in the western US :) ) with the concept being "I'll be pleased and it will never end" instead of the probably more correct "please me for no reason" interpretation you are taking. Either way its like most sayings, people know what they are suppose to mean even if the saying doesn't literally mean the right thing. Oddly "please me no end" sounds like broken English, on par with "i love you long time" (say it in an Asian accent and hopefully the humor comes across, or maybe thats just our distorted offices since of humor.