i left my job today, and some people in work didnt even say bye?

i have worked there 3 and a half years never had a day of sick, done 4 months notice for them cos they really wanted me to stay so they said then its the last time i will see them and they didnt say anything about me leaving not even good luck with your next job i have never had an argument or spoke about anyone behind there back and we always got on well am young and quite quiet but, only the younger people in work said bye and to keep in contact, but my boss who i have done everything for and put everything into work and never stayed off said nothing am feeling pretty sad about it cos he said if i stayed on for longer he would appreciate it but why is he being like this