Let me start out by saying I love to drink coffee, every day, all the time. My wife on the other hand can't stand it. So when Strike King came out with coffee tubes I bought a pack, mostly to bug her.
A few weeks later we were out on the lake going thru an area we called the " bowl", an area around 25 ft. deep, flat and smooth, no rises, humps, anything of note. The fish finder started picking up fish, just off the bottom. I have no idea why they were there, but they were. I dropped the anchor and as it was a really windy day we both cast off the stern using, I really don't remember. No joy after 20 minutes. For something to do I tried a coffee tube. Caught a fish, then another. told my wife to try a coffee tube. Said " it must be the coffee!, I got a dirty look, but she dug thru the tackle bag and found non coffee tubes, same size shape and color., and tried them. After I had caught 7 fish to her zip she finally broke down and tied on a coffee tube, and started catching fish.
I'm not saying coffee flavor works all the time, or for everyone, but that day we had the same line, hooks, technique ( letting the tube rest on the bottom slowing twitching it in) and were fishing within feet of each other, and the fish ignored the non coffee tube but devoured the coffee flavored one. We ended up with 18 fish from that one spot, LM, SM, and Pickerel.
From that day on I have used coffee, caffeine, flavored soft plastic with great successes. The latest being the swim'n caffeine shad. This is the only bait I keep tied on full time. I caught my first fish on it this spring, my last one on it this fall, and many in between.
As I said it might not work for everyone, or all the time, but for me at least 90% of the time coffee, caffeine , flavored baits are my go to, get er done, high confidence baits to use.
Note: in the interest of full discloser I have never caught a bass holding a cup of coffee in it's fin, but you never know.
Jim