There are countless reasons, legal or otherwise, for why a person may not be able to transfer his or her assets. Here are a few that estate planning lawyers run into from time to time:
Spendthrift Provisions - If you're the beneficiary of a trust that was established for you by someone else, chances are there is a "spendthrift" provision or clause in the trust. These types of clauses prevent the beneficiary of a trust from giving away their interest in the trust. These are often included to give beneficiaries protection against creditors.
Pension and Retirement Plans - Except for the ability to name a beneficiary, generally, it's not possible to transfer ownership of a pension plan. Similar problems exist with IRAs or other retirement accounts, unless the owner of the account is willing to withdraw the amounts from the IRA thereby causing recognition of taxable income.
Roth IRAs don't result in taxable income upon withdrawal, but the account owner would give up the ability to have the account grow tax free. There's one exception for spouses of the retirement account owner. In the case of spouses, when one dies, the surviving spouse may be able to "rollover" the account into his or her own IRA and continue the tax-deferred growth of the account.
Non-Public Businesses - If you're a partner or shareholder in a business, the governing documents or shareholder agreements may include a provision that limits your ability to transfer shares. Alternatively, securities laws may hinder the ability to transfer ownership in the business to others.
There are other scenarios where transfers of assets may not be possible, for example, a membership in a country club, businesses that are involved in controlled substances such as alcohol, and certain professional practices.
It's therefore important to consider the types of assets that you own when discussing your estate planning options.