Trespassing. There's laws regarding transfer of property, what you can do on or with your property (zoning and environmental laws), water rights. Lots more, but you didn't want it so big.
Example, someone owns a house and wants to open a medical massage business in the house. If they are zoned for residential use, then they may not (depending on local law) be able to put a business in the house.
The rule against perpetuities has to do with inheritance and not property law per se. And as a court once said "no one understands the rule against perpetuities."
Jake, you have a lot of growing up to do. I imagine a lot of women will own you in the future.