Some webpsges are heavier and some are light - like web pages coded in java are heavier than pages coded in php. Moreover images take more time to load depending on the size. Server speed also matters for loading any webpage . If you are working on many taskes like- watching youtube video , downloading movie from torrent, doing facebook, gmail and when try to open a website it may take some some to load as your internet speed is slowed down due to downloading and other processes.
