What Does God Mean When He Says...

     There is something I don't understand and I have not had the nerve to ask people about. I haven't asked because I don't want to offend people that I look up to, but they are the only ones that might be able to explain to me why it is acceptable for them to use the name of God in a conversation where they say "My God" when they are not discussing something about Him or praying to Him. 
     I know and understand the freedom and grace that Christians have through Jesus' sacrifice, so I'm not questioning basic freedom, but God was concerned about His name enough to include the commandment in the basic "10 Commandments". 
     I have asked some people about this, but never the ones that actually do it, from fear of offending...maybe I should be more afraid of offending God by accepting this use of His name?  I have pulled these verses out in trying to work this understanding for myself~ 

‘You shall not take the name of the Lord your God in vain, for the Lord will not leave him unpunished who takes His name in vain. Deuteronomy 5:11

You shall not swear falsely by My name, so as to profane the name of your God; I am the Lord. Leviticus 19:12

and then I checked the definition of the words, because sometimes we think we know what a word means but we might have a wrong understanding~

     "vain" is~ "marked by futility or ineffectualness:having no real value".
And~
     "profane" is~ "to treat (a holy place or object) with great disrespect; to debase by a wrong, unworthy, or vulgar use".

     If we are using God's name in a casual conversation, are we using it ineffectually? and yes, I know some people will wonder what "ineffectually" means, so here is it's definition~ "not producing or able to produce the effect you want". So if someone is telling you a story and then pauses to say "My God!" is it in vain, or ineffectual or of no "real value"?
     This is probably not a big issue for many people and I don't know that it issue it is to anyone besides me! ....I just wonder if we are glorifying God or degrading Him by our use of the slang term, "My God", that many Christians and non-Christians use.
     I'm just curious, what do you think? Please keep your comments loving and not condemning, let's consider what pleases our Heavenly Father.