Bitcoin works without a central authority or bank using peer-to-peer technology. The management of transactions and distribution of bitcoins are collectively managed by the network. Bitcoin is open source; its design is public, nobody owns and controls Bitcoin, anyone can participate. Bitcoin can handle many different payments that cannot be made with other payment methods, thanks to its many unique features.
Bitcoin is a protocol born out of a small community and has grown rapidly over time.
A "stuck" transaction is a transaction which has remained unconfirmed for period of time which either the receiver or the sender is uncomfortable with. Stuck transactions can be annoying as it means that recipients often consider the senders to not have paid yet, or the recipient needs the money as soon as possible.
Stuck transactions are typically caused by low transaction fee rates. However other things can cause stuck transactions such as spending from an unconfirmed transaction, having dust outputs in the transaction, or being a double spend of another transaction. If a transaction has a double spending transaction and the double spend confirms, then the transaction will be "stuck" forever as it can never confirm.