The title of your post catched me up directly... I was like you for fews months, never upvoted myself (I mean the posts I wrote). But at a certain point I got a lot of frustration seeing that rich people were upvoting their own shitty content and it made me sad and angry. So, to reduce the frustration I started to upvote my own content (with 0.10 cents ;-)). But at least, I felt less depress ;-)

It's great that you says :

i choose categories of Steemizens to use them on both in comments or post rather than use them for myself.

But please, selfvoting on your own post isn't abuse... Especially. But yes, don't upvote your own comment especially when its not adding anything relevant to the post...