Here's my worst experience which almost ended in a tragedy.
I had a 7th gen civic, and the car had this issue of wobbling while accelerating. It was annoying. We had tried absolutely everything but nothing worked.
So one smart mechanic took a measuring tape, went under the car for about half an hour, came out and informed me that 'gaddi aggeyon khul gayee ae' (the car has 'widened' up from the front). Hence when I accelerate, the weight is thrown on the rear wheels, the axles come a tad out and hence the vibration. He sounded convincing so I said go ahead and fix it.
Now He put two washers (spacers) on each outer axle and fixed the wheels. And surprisingly, it worked. The vibration which no one could fix, went away.
That night I had to go to Isd from Lhr. Around Sukheki I started feeling a faint vibration in the wheels. By Bhera it had turned into wobbling. A little further and it felt like my car was swaying all across.
So I stopped at the next qayam-o-ta'aam only to see my wheels pointing in different directions. I jacked up the car and both my front wheels had a good 2 inch 'play' in them.
It turned out that the washers at high speed had pushed the whole assembly out, and a few more kilometers and my wheels would've left the car leaving me toppled over some kallar kahar ridge.
I ofcourse didn't continue my journey, had to replace the whole wheel assemblies, later sold the car, and learnt never to let the roadside mechanics come anywhere near to the suspensions/wheels of the car.