About saying "hi" and stuff / late night blabla

OK so sometimes I truly, genuinely fail to say Hi because I'm a zombie deep in thought. Although I may look like I'm aware of my surroundings... sorry, I was not. I really wanted to say Hi!

In a few cases the presence of a certain person makes me shy and I simply cannot say Hi.

Then there's the rare kind where I fail to say Hi because I'm angry with something. I always regret when I don't greet people for this reason. After all, they are innocent.

In other I think it very important to greet a person that I know or recognize from a common somewhere. If it's someone I've talked to I would say Hiiiiii heeyyyooo!!

But! If I'm insecure about the relation between me and the person... if I don't really know whether we have chemistry or not... I need eye contact in order to say Hi. I'd say that I offer my part of this eye contact 99% of the times. I'm so confused when I don't get it back! Usually cannot greet without it. I know that they saw me, we even walked past eachother, so why no reciprocal eye contact? Does this mean they don't want to say Hi or do they belong to one of my cases above? I'd love to say Hi if you just give me the approval through some eye contact!

Don't worry I'm gonna practice my Hi-saying too...

There's one thing though... ugh. When a friend in common doesn't greet you normally EVER, they even avoid it (don't know why) and/but suddenly (!) at a party or something they don't see you at first, then come to say Hi to the common friend and BAM-oh (!?) there's this forced moment of greetings and they be like Hiiiiii Maria How are youuu!!

What? And a hug? No I'm not hugging you...