why do people dont answer other peoples messages

there is a lot of reasons.
1: they may not like berkata person
2: dont fell like it
3: dont want to talk at the moment
4: dont want to read
5: dont like to read
6: person is mad at other person
7: dont know who the heck anda are
8: not online anymore
9: dont like to type
10: cant read
those are just 10 i thought of. if anda can think of lebih be my guest and do so. ^-^