For example, a common error in C/C++ is to use the assignment operator = instead of the comparison operator ==.
Please, explain why and list which languages have the (mis)feature implemented As far you know. Post what you consider a harmful feature, not what you dislike.
I make a fair amount of small mistakes when I code (things such as getting an angle bracket to the wrong direction). It adds a fair amount of time to my coding because I have to debug several times ...