Your screw pictures are disgraceful .. assuming you are not totally incompetent :D 

I bought a light fitting from the place next to Jumbo in Chanvannes  and the screws were missing ...   the fact I had some in the garage was lucky but not acceptable really 

Oh great .. I'm moving in the new year and was planning to to just buy everything from one of these places.

Maybe i bring my own screws.

Still the same old problem with the DIY furniture assembling. Screws are too often made of low quality tin or aluminum which cannot withstand a battery operated screwdriver... Put it on low-speed and never screw to lock tight.

When assembling panel always try to add a half-wooden match in each hole before screwing and as to the edge of each wood panel made from saw dust/corrugated wood you better apply white elmer glue and let it dry for one hour on each piece. You are investing little for great result. >This would allow your nest dismantle of a furniture piece and authorize a re-assembling without the piece falls apart with wood chips and dust caused by dryness. 

The answer to cheap tin screws is to have your own supply of high quality steel ones that you can buy from Migros Brico.  The biggest problem with cheap screws is getting them out.  The simple act of putting them in the hole destroys the head meaning you can't get it out again.  I took one back to Ikea to complain and the young lady offered me...... a free screw.  Pity she said it in French.

My latest complaint is "long life" light bulbs bought from Carrefour in France.  They are more expensive than ordinary incandescent bulbs and are supposed to last 7 to 12 years.  I moved in my new home just a year ago and usual Swiss trick was played so I had to buy light bulbs for every socket.  Now just a year later, several (20%) of these "long life" bulbs have already failed.  I had to replace 3 just this week.  The bulbs say "Made in Poland".  They were Carrefour "brand" so cheaper than bulbs by say Phillips.