1. just like contactcr, the battery protection film was almost invisible, and it took two hours to figure that out.
2. leaving a flashlight within the reaching distance of a four-year-old and her sister who can climb.
3. loaning flashlights and expecting them returned undamaged.
I almos did this recently! I went to measure and stopped. Then I thought about trying to hit the wrapping on each end, but fortunately decided to be cautious instead. I taped each end and then measured. I only own metal calipers 
Ugh! I was disassembling my Sofirn SP70 to bake it in the oven last night. It has nice chunky leads on it, and a very large MCPCB. Well, the leads were short and I couldn’t get the MCPCB off the head entirely, so I’m sitting there with my iron turned up all the way, re-fluxing the solder joint at the MCPCB, and heating half the head to uncomfortably warm. I’m also tugging with the tweezers to see when the wire comes free… destroyed the insulation on one of the leads. It’s getting a new driver anyway, but I guess it’s getting new MCPCB leads too now.
Anyway, that’s not the first time I’ve done it, either. But I love my curved-tip tweezers…
(The light looks great after baking, though. Pictures to come in another thread.)
I actually had a bad dream about flipping just one of the 18650s in my Supfire M6. If I flipped all of them, at least I’ve got a chance with reverse-polarity protection.
I once set up comparative beam shots by measuring a distance and placing colour-coded markers every few meters, then braved swarms of mosquitos that night only to realise later that I took all of the photos in auto-exposure mode. 
Used all your muscle strength fighting with flashlight retaining rings (head/ tailcap), only to realize that you turning at the wrong direction all the time.
Not really a mistake to some but definitely not something I like. (user error. non-review related)
Loved my Astrolux S41 shiny copper look. Didn’t like the slight brown spots (didn’t know it was patina)
Decided to metal brasso mirror polish it and ended up stripping the protective coating of my copper. Beautiful mirror shine!
But then…the S41 quickly patina into dark brown in less than a day due to brasso slight acidic properties.
Total opposite of my goals.
So I ended up with a light with ugly patina I didn’t like.
Many enjoy copper patina but for me it looks so old,vintage and used now. Ew.
Oh and the copper stinks harder haha.
I feel you :laughing:
To avoid this, I tried to take pictures of the flashlight as the beginning sequence of shots.
The last item reminded me of words spoken by Inuk (Anthony Quinn) in “The Savage Innocents”.
-Someone would rather lend his wife than his sled. You lend your sled, it comes back cracked.
You lend your knife, it comes back dull. You lend your dogs, they come back tired and crawling.
But if you love your wife, no matter how often you lend her, she always comes back like new.-
I can share some of mine
- I wanted to dismantle a Sofirn SP10A for review, and ended up damaging driver before taking indoor/outdoor beamshots. Had to wait some weeks for a new driver to arrive to complete it. LESSON: Learn how to use a soldering iron and use it well or you’ll burn stuff before you put it to work.
- In some reviews I took outdoor beamshots of different flashlights, added them together and made GIFs to show how the reviewed light behaved against others. However, I only pointed out the names of the flashlights above the photo, not “in” the photo. Therefore, it becomes difficult to the reader to catch which is the reviewed light and the comparison ones (unless a very evident difference was shown). LESSON: don’t do this, it is better to have multiple rows of compared beamshots with the reviewed flashlight than putting them all together without properly marking them in the GIF.
- I always feel something is wrong with white balance, shutter, ISO and stuff, but my cellphone doens’t allow me to do super configurations, nor it has the best camera specially for night beamshots. So I end messing it up sometimes, specially in low brigthness, and when mixing tints against a white wall. I am trying to correct it more and more stuff, but it is hard. LESSON: get a device with a better camera; learn how to do combination of ISO, shutter, WB, focus…
- to post some details of flashlights or accessories, sometimes I use camera zoom x2, what makes some things more blurred when seeing a bigger image. When alocating images on IMGUR, I do not always use the higher config possible, so even if one clicks the image for more details, they wont necessarily show up and will still be small and blurred. LESSON: upload images with details in a bigger format into your image host, and allow them to be seen as such in the review.
So yeah, I am silly 
Thanks for another interesting thread ChibiM 
Ohhh yeah. I absolutely destroyed a Tool AA driver trying to unscrew it. Yup, it’s reverse threaded :person_facepalming:
Except for the mileage—the miles of dick run thru that thang.
Simple stupidity with no bad results except for loss of time.
I receive my Sofirn SP33v3 flashlight with 26650 cell inside. Looks great. I decide to charge it up just to ensure the battery is at maximum once I start testing. I plug it in and the LED starts giving this strange flashing of red on/off with one blue tucked in the mix. It keeps repeating. That doesn’t seem normal. I wait a few minutes to see if anything changes. Nothing.
Idiot me… forgot to take out the battery contact blocking disc. The LED indicator was basically saying, “I do not detect a circuit!”