What's the simplest yet dumbest mistake you've made in this game?

I couldn't figure out why my coin runs weren't making near what they were, when I hadn't changed anything except for getting higher coin bonuses.

I landed myself a pretty decent set of perks in the 1,000 🌊🌊 of Tier 10, maxed everything by wave 300 but EHLS/EALS, reset a couple of cards and left it to do its business!

Picked up my phone to see that 2+ hours have passed and I've only made 45+ billion coins (WTF??!). Now I know something is up, I should have been up to 200+ billion at this point.

I scrolled through cards, labs, modules/sub-mods and anything else I could think of, then I clicked on my Ultimate Weapons tab to see everything is normal and in sync BUT MY BLACK HOLE!!!!

FOUR DAYS, GUYS!!! FOUR FREAKING DAYS!!!

Roast me for not noticing or whatever have you but that's my simplest yet dumbest mistake so far.