Even more delay has happened with me couple of times in recieving even 1 confirmation for my bitcoin transaction.I think upto 12-16 hours i have waited once getting 1 confirmation but you doesnt need to worry about it,it only happens sometimes and should get confirmed at some time.
Few months ago happens that someone send transfer without fee and transaction was waiting 3 days in queue.. after three days come back to the wallet.
Standard fee is 10k satoshi. If someone want be sure that transaction will be realised faster is better to pay more than 10k satoshi fee..
Its just a commonsense thing that we should pay even more satoshi in able to transfer a way more faster rather than putting up only a small amount. This case may really depend on the user, if hes on the rush on transferring the bitcoin then he should add up transaction fee in able for bitcoin transfers would be fasten and if hes not on the rush then any fee would do. There are really times that confirmations would really be long .