I try to help a bit on the question, there is more than it seems:
1.) transactions are basically a transfer of value from one address to another address. When a transaction is sent to you (to your address), then it should have a confirmation in one block, before you can spend it. The miner basically takes all transactions, verifies them for correctness, and puts them into a block.
If you don't wait for a confirmation: the use case would be like this:
your wallet get's notified, that a transaction has been sent to you, and you don't wait for the confirmation. You try to spend the fund of this tx for s.th. else, send it into the network, and you will remark, it does not get confirmed. This might happen, because the original sender has sent another transaction with the same origin of funds to another address (not yours). So in this case, you would "believe" to have received funds, but you actually don't have the funds. It's a trust issue. In general it is said, that 6 confirmations (after ~1 hour) make it sure, to spend the funds.
2.) You are right, it is not in your control. The miners make sure, that the network is working correctly, and security is kept to the highest level. So they provide a service, and get payed as incentive with block rewards and fees.
So @pebwindkraft even if my transaction does not come into the block.. if 6 others have authorised it will the money be sent? – Ish – 2017-12-21T09:43:26.073
slight correction: a confirmation means, that it is in a block. With six confirmations I meant, that several blocks (each at ~10min) have passed, so after an hour it is secure to spend the funds. IN this sense, yes, if others have confirmed (we don't say authorized) the tx, the funds are transferred. As long as your tx is not in a block (is not confirmed), you cannot be sure, to "have the funds" in it. – pebwindkraft – 2017-12-21T09:57:40.450
ok @pebwindkraft thanks for clarification. But one last question.. These miners act as the deciding authority. So I have to wait till the miner who has my transaction to succeed in the hash puzzle.yes? Also how big is a block? – Ish – 2017-12-21T11:55:29.560
This is two questions :–) One can argue on the role of Miners and Nodes, but yes, in the end one of the many miners put your tx in a Block, and propagates the block to the network. A block can be up to 4megabytes big. – pebwindkraft – 2017-12-21T12:02:46.107