Blockchain is the best technology to have visited humanity, this is honest affirmation. It is certain that when you do a transaction of bitcoin to another party, despite the delay or low fees paid, if it is reflecting on blockchain through your TX, you just need to go sleep on your water bed because it must delivered eventually.
If about doing P2P transfer and you don't use escrow, this is risky if the other party is fraudulent to scam you, he may photoshop, edit or send the TX of another transaction and you may be gullible to send fiat without checking blockchain first. So always confirm from blockchain using TX, if it not scam, you must see the transaction there as unconfirmed. In such instance, you just have to wait for it to confirm.
The need for this glad story, information and eye opening is because I recently had the experience of a transaction that took a look of time to deliver, maybe close to 3 weeks and 1 month , it later got deliver at last. However, it has always been in blockchain there as unconfirmed. It actually got my nerves raising because it is the first time to have such delay, before now I have had lesser delay like 2/3 days but not a month.... Finally it got confirmed.
The point here is blockchain will always reflect a genuine transaction as unconfirmed, you just have to wait.
It will always deliver despite low fee paid once reflected in blockchain.
Miners must process it at there own time
Major reason I can confirm for my transaction delayI did the transaction at a time bitcoin was highly volatile and bullish and immediately I sent out coins (with low fee), I observe that price skyrocketed and this could mean fees also increased So, I think the miners left my request to process higher fees transaction and they kept processing such coins that were coming in high fees...lol. Who doesn't want additional pay
But I was seeing my transaction on blockchain. Therefore, relax if you see your transaction on blockchain despite the delay. Try and take your mind of it and look for other money you have or that you can , so you don't worry too much.