I read some other posts about this. Trackpads work like this... There is a charge underneath them that creates an opposite charge in your finger. The computer figures out exactly where that interaction is happening, in order to know where your finger is. This means that there are electrons being moved (either pushed or pulled) through your finger tip as you use the trackpad. The nervous system is a highly electrical system and the hands are especially sensitive instruments!!! Most people may not be bothered by the interaction. I'm sensitive to small electric current. The trackpad of my 2012 Macbook Pro causes me fingertip pain, and I can feel the current easily even on palms resting on either side. It has nothing to do with finger pressure or some kind of slow reacting allergen, as guessed on other posts. It's an instant and immediate sensation, relieved upon removal, but leaving a dull ache that I can quickly massage out. I've used laptops since like the 1940s, but whatever is going on inside this particular one is unacceptable for me. Has Apple bumped up the charges to gain more precision I wonder? OK, it's fluid and sensitive as ever a trackpad was, but it's not worth nerve damage inside the vessel that carries my soul. Also, just because the electricity doesn't bother you, doesn't mean it aint there, works the same as everybody else.