This is quite a loose question but I was very surprised to find this out so thought I would ask.
I was running a script where I defined a function handle call it g, which was acctaully very simple (basically a linear function). Insdie the scrip I called a function which took as one of its inputs the function handle g, and applied it to a fixed vector of length 200. My code was taking ages to run and everytime I paused the code I found it was computing the function handle of the vector. I decided to apply g to the vector and enter this value as the input to my function (instead of the handle g itself), now my code runs much much faster... I dont really get why this is happening, is this obvious?