If someone seems not to like me I just figure I'm not their cup of tea. We all have people we mesh well with and others we don't. I just move on to someone that i can connect well with.
However, I would say if you find that many people are having an adverse reaction to you and it's not just isolated incidents, maybe you should take a look at that and see if you are inadvertently doing/saying things to have that type of reaction. Sometimes we carry behaviors that we're unaware of that push people away. If you're really brave and are ok with some constructive criticism you could always ask directly if you've done something to warrant that reaction in them. You might gain some insight, but again it really depends on context.
I don't know about blocking people- personally, I find that whole "you're dead to me" approach very reminiscent of JWs. Unless there was some sort of abuse or it was very detrimental to my well being, I'd just ignore them and not do anything at all. Sometimes having any type of reaction to something just gives it more power. Just my two cents...