The reason they are bad is that intermediate results are never named (and thus are never explained). In simple situations, it's possible to infer from the context what the author's intention was, but in more complicated cases, if you want to understand someone's code, especially if it's written in the way you did, you'd have to "disassemble" it into simpler operations, name the variables (after investigating or guessing the purpose of each operation) and then try to come up with the full picture of what's going on.

Also, as a style suggestion: avoid using backslashes. In your situation, you could just put dots at the end of the line and it will be enough to not need the backslashes. It adds noise to your code, i.e. characters that add no meaning, just sort of a "scaffolding" to hold your code together.