tl;dr: I just lost days worth of exploration data because I wanted to land on a planet before going to bed.
I started in Elite Dangerous a couple months ago. At first I wasn't crazy about it, but I was able to buy an ASP Explorer after doing a wing mission with friends. Started grinding missions to get Federation ranks so I could visit Sol. After that, I decided I'd try exploring. So I spent almost an entire afternoon and night jumping to systems, scanning them, mapping planets, and then flying back and turning in my data at a starport. I got 1,000 LY away from Sol, got around 46 million credits and had a good time.
Now I'm really into the game and wanna keep exploring. About a week ago I take off on my mission to leave the Inner Orion Spur. Spent a couple nights jumping my way to the Outer Orion Spur, using Neutrons, scanning every system and mapping the valuable bodies, until I finally make it and get the achievement for leaving the Inner Orion Spur.
Now time for the long trip back. Did the same thing going back, jumping to systems, scanning, mapping, using Neutrons.
I was about to call it a night after scanning 3 terraforming candidates in a system. One of them has planetary landing. I just got Horizons last week and have only landed on a planet once, so I think why not land on this one before logging off. I fly to it, have a beautiful approach, going to land in this big crater, when I realize that the ground is coming up faster than I realized. I start pulling up and thrusting up, but it's too little too late, my ship bonks into the ground. All the HUD immediately disappears on me and I'm in shock. My ship is gone. Days worth of data is gone. Definitely had over 50 million credits worth of data, maybe even 100 million, and it was all gone in an instant because I wanted to do a cheeky planetary landing before going to bed. I tried closing the game quickly hoping it would undo it somehow, but, alas, my ship was still gone. Really ruined my whole night. Want to die. Was SO looking forward to turning in that data and seeing how much I would get for it all. Now I'll never know.
Guess I'll just have to get back out there and do it again.