Another reason could also be the fact that devs usually only ever run development builds of the software. So you end up dismissing slowness due to this ("I am

Another reason could also be the fact that devs usually only ever run development builds of the software. So you end up dismissing slowness due to this ("I am sure this is faster when compiled in Release!"). I've made that mistake before until it was so slow that I decided to compile a Release build which was just as slow and found out that a regression was introduced. Automatic performance monitoring for 'tasks'/services/computations is relatively straightforward but not quite as easy for UI interactions so these often get ignored.