I just had to replace my old gas cans with the yellow plastic nozzle with a simple plastic tab at the end. They had a similar tab on the back of the can to allow air air to enter the can as you pour so you don't get large splashes.
Well the new "beauty" that I just bought is all sealed except for the black nozzle. The nozzle itself has this retarded design marketed "to not spill as you pour." Basically you turn the can upside down, stick the nozzle into the tank you want to fill, and push down on the can so it opens the spring loaded valve in the nozzle itself.
I can say with certainty, that I have never spilled so much gas in my life as I have in the last week using this piece of crap. When you initially push down the gas splashes all over. When the tank fills you can't see it because the nozzle is in the way and you get gas spilling all over. trying to hold open the valve and just pour the gas usually yields about a 1/4 ending up all over the outside of the tank and my hands.
The kicker was a guy ran out of gas outside my house. I drove him to the gas station and he bought one of these gas cans, filled it up and tried pouring it into his car. The nozzle wouldn't fit into his car and he maybe got 2.5 gallons out of the 5 to pout into his car tank.
If anyone out there still has access to the old style gas cans with the simple pour spout with an air valve on the back (probably only "red staters" I'd imagine), please PM me and I will send you cash to get my hands on a gas can that won't kill mine and my customers grass.