The word for 'vain' here, comes from an ancient Hebrew verb that means 'to err'; hence 'vain' in the original Hebrew could be translated also with 'aberration (through sin)', or 'vanity (through sinfulness):' as there is no avail against the Almighty.
This commandment can easily be denied or negated and once one has learned to curse, unlearning is difficult. One can also diminish this commandment by using alternative expletives such as 'jeewish' or 'damn' instead of the all out G.D. This all shows that our hearts are full of irritation and violence. The idea that one must simply get it off one's chest, is a lie. For there is no end to anger. Constraint is nobility here.
Yet, even this commandment can be exaggerated, for instance when one is way too careful and attempts to avoid using God's Name, out of undue fear of using it in vain; or when one insists always on saying 'Lord Jesus' and never 'Jesus' referring to His being a human once on earth (even though we do not know Him now anymore according to the flesh).
I] When you curse, you take Gods Name in vain. In doing so you reject His All-Holiness, His Person. Actually, deep in your heart, you curse the One and Only true God.
II] In doing so, you prefer (an)other god(s). You want to be your own god through the idols (read: ideals, ambitions, etc.) you have set up for yourself.
IV] In rejecting God, you reject both the eternal sabbath, rest and peace for your soul and the timely sabbath from your evil works. It is only just if the All-Holy One then also rejects you!
V] You despise the heavenly Father and say no to the New Jerusalem, the invisible Church that comprises all true believers.
VI] You kill God in your heart and burn Him in effigy emotionally. In doing so you violate your own soul that is totally dependent on the Almighty. Do not bite the Hand that feeds you.
VII] When you curse you commit spiritual whoredom against God with the devil, the fallen angels, along with anybody that does the same. You, a mere mortal, set yourself in array against your Maker. Demons fear God, but you in your narrow and abased consciousness, make a mockery of it all.
VIII] You rob the honor and dignity connected to Gods Name. His Name is above every name and worthy of everlasting praise.
IX] Your life and everything it stands for is a lie. Only in honoring Gods Name will you stand in connection with the Truth.
X] Whatever it is you covet in your life, it is all based on the abasement of God and the exaltation of your own self. But he that exalts himself, will be brought down.