This is the single biggest gripe I have had with KSP since I got this game years ago, having a component that is facing the wrong way which will prevent it doing what it is intended to do.
80% of the time this is with docking ports that just look the same on the front as on the back but you cannot dock on the back side.
Spending hours and hours trying to build a space station only to find out that 1 of the 10 docking ports is facing the wrong way after docking a number of ships, this usually just makes me hit the X top right and wait a few versions & mod updates before starting over.