Thats a guy
Don't let @Boombox deceive you he wants attention
Lol it depends on network propagation more than anything. Next time you send a payment take a look at the propagation
it's more accurate if you use your own bitcoin client that is running the full node - updated to the latest block.
it calculates the appropriate transaction fees to pay to the network to get your transactions through. if you're using wallets like mycellium or circle then you'd expect more delays than using your own bitcoin client.
well web based btc wallets usually don't have an option for making the transactions fees bigger or smaller, it's normally automated.
if you're looking to using btc as a medium of exchange, it's best to download bitcoin core on your pc. it will take up roughly 80 GB of your hard disk space tho, and it will growing over time. but i guess that's too much of a hassle.