Couple of weeks ago our Electric Fan Oven failed, I'd already replaced the heater element twice before to keep it going but when the 'timer' buttons pushed through the control panel and fell behind enough was enough so I decided to order a new oven and a matching GAS Hob as a treat.
I can fit the oven myself but couldn't be arsed altering the gas (more on that later) and coupled with Mrs_Welly's insistence that I'm not allowed to do "big jobs" because: Heart Attack I actually paid for the 'delivery and install' service. No-one but no-one ever works in this house apart from me so my 'supervisor' senses were on high alert

The Gas Hob was an identical fit to the old one so the gas was tested, disconnected, reconnected, tested etc all fairly normal and there was much activity with battery drills for the fixings that pull the hob down clamping the Hob down onto the worktop.
The Oven is 'built under' so slides into an empty kitchen base unit effectively, and the Gas Hob is sunken into the worktop above. Old oven came out and the two early-twenties age lads started fixing the large L-Shaped metal angles either side of the cupboard onto which the new oven will 'slide in' and be retained with screws at the front. 'Clank'

Anyway we all agreed that the gas needed altering to clear the cooker's casing and that this was outside of their remit so the Oven was removed. I commented to the lads that the Oven looked 'pissed' sitting about 5mm higher one side than the other...."oh that's alright there's adjustable feet underneath to sort that.....BYE BYE......
About a week later I got my Gas Boiler Serving man to come down and alter the gas for me, I had been refunded the Oven's 'install charge' so I was covered financially. Before he arrived I tried the Oven back into the hole and saw that there was definitely NOT any adjustable feet and that they'd actually fitted the L-Angle 5mm higher on one side of the cupboard FFS. I had to remove the Angle, measure and re-drill the fixing holes further away so I could re-screw it just 5mm higher - SORTED! - why couldn't they do it right in the first place

Next when we disconnected the gas hob we noticed 2 of the 4 hob 'clamps' were loose - turns out they had wanged the screws in with a battery drill, these screws are like electric light socket screws and going into a thread tapped into sheet metal about 2mm thick at best so they must have instantly stripped the threads with the battery drill and f*cked off without saying they'd damaged them.
Now - because I'd had another tradesman working on the hob I've got no chance complaining against the original lads so I just kinda nipped in two slightly coarser/thicker screws and fixed* it myself in the end.
MY POINT - what is the obsession with everyone whazzing screws in left right and centre with bloody battery drills?

Soz for long rant but that's the last time I get a 'professional' here to do something.