I was around 16 years in the early 90s and i bought a digital watch (different brand) with a lot of functions. I remember when I came home from the shop. My aunt was visiting. I explained that the watch could keep lap-times for two separate cars. Without her saying anything, I realized that this was totally useless and I regretted the purchase.
I feel like most gadgets I've purchased in my life were totally useless. Don't really regret buying them though. Even though I'm pretty sure they're all in landfills now.