Auto repair people are desensitized to know-it-alls.
They deal with them daily.
Time will tell weather you are really the dumb one.
In the meantime you could do a parasitic draw test on your vehicle.
Disable the underhood lamp, shut everything off. Remove the negative battery lead, insert your 0-10 DC ammeter in series with the removed cable and the battery negative terdminal. Leave your little cigarette lighter power charger connected 
Do not skip this step - short across the ammeter with a cliplead or something similar. This charges any capacitors on the load end. Remove short and read current.
Anything over 175 mills will kill the battery over a few days. Over time it will make the battery into junk due to repeated deep cycling.
Repeat with your little harmless charger disconnected.
Trouble tree branch one:
Buy everyone at the shop lunch.
Trouble tree branch two:
Continue to carry jumper cables around because your replacement battery will probably die again at the worst possible time.
Remember the definition of insanity. Doing everything the same way but expecting different results. This only works with computers and some women.
