I've had several "warnings" in my driving career.
When I was 19 and visiting a friend near Columbus, Ohio, we'd gone to a 24-hr Denny's around 3am and were dropping off someone before heading back to my buddy's place. The officer pulled me over after I drove away and asked what I was doing. I told him that we'd been to Denny's, we dropped someone off, and we were heading back to my friend's place to go to sleep. The cop again asked again "what are you doing" and I repeated that same story. He then told me to get out of the car, said "you're mine," patted me down, and locked me in the back of his cop car. He said that if my friend was underage (he wasn't), I'd get a "contributing to the delinquency of a minor" charge. After a long search, they found nothing, then the cop told me that if I hadn't taken an attitude and just been truthful, he never would have searched me. This was a good life lesson that even if you're not doing anything wrong, the police can still mess with you.
On I-80 EB, this time near Minooka, IL while we were heading to Ohio for Christmas circa 2010, I was pulled over and given a warning for going "72 in a 65". Knowing that my cruise control was set at 68 and based on the officer's line of questioning about if I had any drugs in the car, I believe this stop was a pretextual fishing for a drug interdiction search. Luckily, Illinois has both raised its speed limit to 70 and legalized cannabis, so these types of stops should be less common now. I drove away playing an appropriate NWA song on my iPod.
Back when I was married (in the mid 2010s), my then wife was driving on I-80 EB in Nebraska at night while I was sleeping in the passenger seat. She was going 80-ish, and for some reason abruptly pulled into the right lane (probably to let someone pass). That woke me up just to see us closing quickly onto a state trooper-I thought she was going to hit him! Luckily, she was let off with a speeding warning, but it scared the heck out of me.
The last warning I got was in southern Utah on US 191 in 2018. I was heading downhill and coasting while downshifted when a state trooper decided I was "following too closely" the only other car on the road. As I was headed to a professional training in Arizona with another gentleman with my pup in the back, he let us off with a warning. Again, I assume this was a fishing expedition.