As they say on TikTok... I'll go first! 
So, I'm not an engineer, but I did come up with a nifty solution to a persistent annoyance.
I used to work for an electronics component supplier as part of the High Security Team. Team members had specific clients and orders that only they could handle. This meant we had a bunch of stickers to apply to items or packaging, and these stickers came on rolls. Imagine having about 10 rolls of different stickers cluttering your desk at any given time. It was a nightmare! You had to peel off each sticker with your fingernails, which meant taking off your gloves (we wore gloves to avoid getting fingerprints on delicate components—I've got another story about that, but I'll save it for later! 
). Plus, the rolls would unravel and scatter all over the place if you weren't careful.
After getting fed up with constantly rewinding rolls and doing the gloves-on, gloves-off dance, I decided to come up with a solution. Inspiration struck when I saw a box of hole punch reinforcer stickers in the stationery cupboard. The box had a clever design that dispensed the stickers automatically when you pulled down on the backing paper.
I scoured the office for scrap materials and found the perfect box to hold five rolls snugly. I cut two slots in the sides of the box and used a piece of stiff tubing to hang the rolls. I also cut out four circles of card to place between the rolls so they could spin freely without getting tangled. Once I threaded the rolls onto the tubing and hung them in the box, I added two narrow strips of card along the top edge and the front of the box. When the roll was threaded underneath these strips, pulling down on the backing paper would dispense a sticker that you could easily lift off with gloved hands. Problems solved! 
My colleagues loved it so much that they 'commissioned' me to make one for each of them too! 
So, what's the most innovative solution you've come up with for a tricky engineering problem? I'd love to hear your stories, whether it's a clever hack, a creative workaround, or a full-blown invention!