My first attempt as a youth was Cardiff to Cambridgeshire. Being a newbie I thought it best to try and travel as the crow flies. It took me fifteen lifts and a night dossing down in the woods. I didn't realise that it's better to go the long way round on faster roads and motorways.
My second attempt was Cardiff to Germany, where my brother lived. I got mugged and attacked with a broken bottle in London en route and had a vein and three tendons severed by the glass (using my hand to protect my face). Almost died through blood loss but carried on after three days in hospital, albeit with my hand stitched up and in plaster and my face full of scabs after being kicked in the head. My lift was all the way from Greenwich hospital to my brother's town in Germany (via the ferry).
Never had any problems hitching in the years thereafter though.