Luckily I have never lost any action figures as a child. I had Master of the Universe, Thundercats, The A-Team (most of them fell apart) and I did get rid of the small figure play set and the van. When I moved house when I was 16, I found all my old MotU figures and Tcats....and I wished I had left them in the attic as being 16, I didnt care much for them. One by one most have been lost or been damaged and I have lost Lion-o, Mummra and Panthro with his accessories. I do have the headresss of Mummy ra and the sword of omens of Lion-O. However, I also collected Lord of the Rings and not getting the line when they were cleared at Tr Us. However, fellow collectors, ebay is king! Have picked up so much. Now, if I can afford it, I get it, take a gamble and enjoy it, even if it is a duplicate.
Ones I do regret are not getting more of Star Wars when a pound shop were selling them off for a £1 a piece.