OK hilarious it may appear to some maybe even most people here but emergencyman is right.
These small issues are often a matter of customers perception or poor communication between client and contractor.
When I replace a part I leave it beside the appliance and when tidying up ask the customer do they want me to dispose of it or do they want to keep it, a simple question the old part is theirs the vast majority are pleased to see it gone but there have been a small minority who say leave it.
I had a Gent ring me asking why I had taken the old ignitor from his pellet stove, I was able to answer that I had asked his wife if she wanted me to dispose of it his reply was that he wanted to check if it had indeed been broken or faulty, without laughing I offered him the waste bag out of the van so he could check if every component was faulty for me.
Ask the customer, we can't read their minds, also make sure you apologise when talking to this particular Lady explaining that to you it was rubbish and you wanted to leave the work area clean and tidy.
Try to make a positive out of what at the moment is very much a negative.