Hail size is an indicator of the strength of the updraft in a storm. Severe storms and tornadoes are often accompanied by 1 inch (25mm) diameter or larger hail. When you see hail that big, it's time to be heading for safety if you can. About 6-7 years ago a few pieces of 2 inch (50mm) hail landed in my yard accompanied by a large amount half that size. Luckily no damage, but that storm went on to produce a brief small weak tornado a few minutes after it passed over my house.
A friend had some pretty good hail dents in his 2 year old BMW. He used one of the 'paintless dent removal' services here which removed the dents so perfectly that I could not find any evidence of them at all afterward. I never thought it was possible till then, but I'm a believer now!
Phil