I'm no expert, but...

The shower faucet in my bathroom has had a bad case of the drips.  For a month  or so, I seem to have been the only one who can close it in such a manner that it doesn't drip...but this last week or so, even I seem to have lost that ability.

With all signs pointing towards it being a bad cartridge, I watched a video or two and said...yeah...I can do that. 

The job started well.  I correctly isolated water to the house(last time I tried a shower repair, I didn't do this correctly.  Things went BAD.  Really BAD.  It's why I'm making a big deal out of fixing my shower this time), and got things taken apart with no problem.

Than we had a problem.

The shiny cartridge on the left is what the internet had led me to believe I would find inside my shower.  The scuzzy looking one on the right is what I actually found.  Now, even though my butt-crack occasionally shows up, I'm not a plumber.  Even so, I recognize a problem when I can see one...I mean, one is translucent, the other is white!  That can't be right!  Screw you internet.

Because I'm learning, I headed back to the hardware store, and this time, I actually brought the cartridge I removed from the wall with me, and completed the job. 

So far, so good.  I turned the water back on, and no dripping.  I turned the water on and off, and no dripping. 

Watch out, Bob Villa.