Avoid Boolean

It is possible to misuse a boolean parameter to do something stupid. For example, if you want a function which converts your data into a string representation and another which converts it into integer, you could do something like this:

    object Convert(bool stringornot)
    {
        if (stringornot)
        {
           // return as string
        }
        else
        {
           // return as integer
        }
    }

Oh my god that's totally unreadable. Oh my god my god my god. With this single example, I am now going to make a straightforward suggestion. Do something better. Have two functions for the alternative cases. E.g.:

    string ConvertToString()
    {
        // return as string
    }

    integer ConvertToInteger()
    {
        // return as integer
    }

Now, the masterstroke. Using the extrapolation design pattern, I will now propose that no function should ever take a boolean argument to express anything which might affect its logic. This ringfencing will cause you to jump through hoops. I would also suggest you try to avoid passing more than one parameter to any function and would also suggest that each function have a maximum of one line of code in it.