WHAT is humility? (7 sins & 7 virtues)

[SorenVC]

I know this "7 sins and 7 virtues" isn't really in the Bible, but I would say it is agreed upon to be equally true and as "official" as the Bible. If you didn't hear about it yet, here it is.

https://en.wikipedia.org/wiki/Seven_virtues

Virtue / Sin
Chastity / Lust
Temperance / Gluttony
Charity / Greed
Diligence / Sloth
Kindness / Envy
Patience / Wrath
Humility / Pride

Now regardless if you believe these virtues are good for you I wanted to ask you what you think of humility, since pride is the biggest sin and therefore humility is the biggest virtue. Humility is like thinking less of yourself "I am not important".

The Oxford Dictionary, in its 1998 edition, describes humility as a low self-regard and sense of unworthiness.

So I have two questions for you. WHAT do you THINK of humility is it good or bad? And how come many times people say they are "proud" of something they are or that they did. Isn't this feeling bad? Because religiously speaking it is. Correct me if I'm wrong.