I don't know if it's ego or just the "here and now" belief and desire that "this time" will be different that causes them to not consider that the last time or many previous times, "their way," won't work.
H consistently tries to carry in too much from the car at one time. Too often, something gets dropped and broken. Occasionally, he's able to carry in a lot, but the risk isn't worth it. Who would carry 10 things and a baby if half the time you drop the baby?? (that is just an analogy).
I can't tell you how many times glass jars or beverages have been dropped by H because he's carrying too much. Today, we came into the house, I asked him where my drink was, and he sheepishly told me that he spilled both of our drinks (which were two DIFFERENT drinks) and then he proceeded to pour the remains of one drink into the other ((yuck) and tried to hand me this disgusting mix of iced tea and diet coke. (how insane is that??). I grabbed it and dumped it in the sink and certainly gave him a well-deserved rolling of my eyes. I'm sure he thinks my reaction was bitchy, but hell, how many times have I told him not to carry too much at one time.
Each time I warn him, he angrily insists that he won't drop anything. One time, at my mom's birthday party, my mom received some boxes of expensive fragile china and glassware. H piled them about 8 boxes high (seriously) and wanted to carry them out for her. I told him, "no, that is too much to carry at one time." He insisted. I told him that we couldn't afford to replace the items if he were to drop them. He still insisted. Thankfully, my mom overheard this conversation and said, "Those are my gifts, and you cannot carry that many at one time." That forced H to put some down. Otherwise, he stubbornly would have gone ahead, likely tripped on something he didn't see, and crashed a bunch of boxes.
Now, will he learn from this? I doubt it, because he hasn't learned from the 1000 other times this has happened. This time it was just 2 drinks, but it's been an expensive Bose stereo one time, a brand new iPad, countless number of glass-jarred groceries, and numerous cartons of eggs. These things aren't free. One time he dropped a carton of eggs right in front of me, and seeing my reaction, quickly insisted that: "none of them broke." Sure, I open the carton and there wasn't an intact egg in the bunch. In his mind, "saying" that none broke makes it true. (how insane is that?) One time he insisted on carrying a large TV all by himself to our on's car. H gets all the way to the car, but he was dragging the cord on the ground which caught on a tire causing a comedy-show-like fall, right into the side of the car, breaking the TV and putting a good sized dent in son's car.
The "memory-less system" rears its ugly head all too often. My guess is this is partly from poor parenting. He wasn't adequately disciplined when he did this stuff as a child, and some of it is just "here and now" thinking.