Simple situation. I make a transaction and set to low fee by mistake. Now i need to wait days for processing. Why i cant just cancel it and resubmit with higher fee? Ok, maybe this could create problems for services that dont check conformations on deposits. Another option. Why i cant set higher fee for transaction that already in mempool? As i know there are special wallets that allow to do so. Why this feature avaliable in only several not popular wallets?
As for me, option to make fee higher for mempool transactions is profitable for everyone. Miners will earn more. Recipient will recieve money faster. Sender will be happy. Why not?
I understand what you are talking about personally this happened to me once then I just send them on normal fee. The thing is there are wallets who are going to allow you to change the fee of the transaction once you have actually sent it.
For example in samourai there is such option , you can change the fee to normal or urgent after you did send the transaction and that works wonderfully but not in every case. I don't know why but mine never works. Maybe something with the settings idk but yes it's possible.
There is a feature called RBF to bump fees, but this depends on what wallet you're using to make transactions. Most custodial wallets don't apply this feature so you won't be able to bump the fee. The best solution is to use a non-custodial wallet like Electrum (this is popular, unless you define "popular" by having lots of ads on exchanges).
With wallet supports Replace By Fee (RBF), you have to turn it on, mark your transaction as RBF at the time you broadcast it initially. If your transaction is RBF, you will be able to bump the fee later. If it is not RBF-transaction (RBF is off), you will not be able to bump the fee later. In the second type of transaction, the last thing to do is Child Pay for Parents.
[TUTORIAL]getting a low-fee transaction unstuck by creating a CPFP with electrumEven after this sometimes it does not work. I did contact the customer care and they just told me that it was simply not possible and therefore I waited for either the transaction to get rejected or either for it to have like 40 confirmations but then again it's good if you have time and don't really care about the current price.