There was me having driven, with a full car load, over 600 miles up to and around the Lake District, then back down to Blackpool, when with just 5 miles to go before arriving at our holiday home, on the M55 my n/s rear tyre decided to deflate!! 
No problem I thought, until I realised my trolley jack was back in my garage in Ashford as the boot had to be filled to the brim with my adopted daughter's families luggage and there had been no room for it all!

Unpacked car of occupants to stand on the embankment, and then boot of all the luggage, extracting one good spare wheel, tools, and that bloody scissor jack!! 
All went well to start with until jacking up the car and taking off (very easily for a change!) the offending wheel.........that darned stupid contraption of a jack decided to topple, with the wheel hub ending up in the road surface!!

Fortunately I managed to place the awful jack back under the jacking point and very carefully, with old wheel being progressively pushed under the rising car as a safety (for my sanity!) measure, jack the car up enough to place the spare wheel on the hub, that is after I had straigtened the metal hub backing plate which had been crushed against the bottom of the brake disc! 
Anyway all was ok in the end, and I did not require my AA breakdown cover, but I will now vow never to leave home again without my trusty trolley jack! 8-) 8-)
Who was the bloody idiot who thought scissor jacks were a good idea?
Lizzie, welcome back, you've been much missed m'dear.

Regards the stupid scissor jack, carry a bottle jack in the boot, I do, far better than a stupid scissor jack, safer too. works like a trolley, ie: hydraulics, but takes far less room.
My bottle jack is no substitute for a trolley, but far far superior to any SSJ. in my humble opinion..

Dodger