Quoted from PinRob:
The dumbest - Really?
If you willingly handed over something to someone- that’s not stealing. True
You gave them the item (albeit on loan) of your own free will. True
Stealing - is taking something without the owner’s consent. True
All you can do really is ask for it back - repeatedly if necessary as shown here. Ask a local lawyer or law enforcement officer for the true answer according to where you live. Tell them when asking this about a pinball playfield and a set of pinball plastics.
A criminal charge of theft (or larceny) generally requires the specific intent to permanently deprive another individual of his or her property.
Thus, not returning borrowed items is still theft.
BTW remind me not to borrow you ever anything, since you seem the opinion it is now yours to keep.