Depends on why. I think an explanation is best, unless the other person is rude/stalker/vulgar/hostile.
Just say I am blocking your *** cuz.....what reason it may be then block them.
I just unfriended him, but still replies to his messages. Now he don't message me. He understood the reason. But I think communicating the reason is important.
Then blocking is the better option. But you should communicate the reason once, not just for yourself or for terminating the communication in better way, But to make him realize his mistakes so that he should not repeats this with any other. It's about trying to give him a good bye lesson.
Depends on the person and situation.
I don't usually break up with my friends. lol But they would have to really overstep their boundaries for me to block them and if I did...yes I would tell them why. Unless of course they are pervs in which case I just block right away with saying a word.
You bid them farewell
I would talk to them and let them know how you feel. I think it'd be rude to just block.
Typically ppl delete and start over..