I think this is a big factor in estimation inaccuracy for really new programmers - but it is pretty well fixed by project managers following estimation rules of thumb - like double it and add five days... The bigger issue that I am less certain about being teachable is the experience side of things. I've worked in industry for a while and I know how long different sorts of patterns will take to write and what sorts of complications different sorts of add-ons will add to those numbers. Some projects are about where my naive brain fifteen years ago would put them and other ones are wildly different due to complexities that aren't visible in a surface level examination. Learning to sniff out those complexities seems to just take experience (not with every individual scenario - but it's a pattern analysis thing).