Once in a while the bonus makes a marked difference, but those times are pretty rare in my experience, and often rely on the DM saying something like, "Wow! You needed to roll that 17 to stay alive!" thereby letting the player know that without every bonus he had, the PC would be dead.
That said, 5e is a very forgiving system where you are rarely even in a situation where one roll will determine life or death, and usually saves occur every round until successful. Most spells and abilities are impediments intended to be in effect for at most a round or two, and the rest deal damage and are simply resource drains(HP and healing slots/items).
I've also noticed people like to use, "Well that extra +2 means 20,000(made up number) more damage over 20 levels!" which ignores that 98% of games don't go 20 levels, and that the 20,000 hit points is spread out over 10,000 monsters. A billion dollars is a massive amount of money, but spread that over the population of the U.S. and it's a paltry threeish dollars each. That small amount of extra damage per creature doesn't mean much on its own, but means even less in 5e where much of the game balance is expressed as monsters being bags of hit points. 5e monsters have more hit points than they did in prior editions, reducing the meaning of that bonus damage even further.