What a ridiculous post.
Flash is without a doubt the most useful summoner spell in the game.
If bad players use it just to engage knowing they can most likely get out if things turn bad, that's just a poor choice by the player.
I can not count how many times flash has allowed me to finish off a kill or steal baron or any other number of situations that I have thanked the gods I have flash for, other than just getting a little distance from the enemy.

The only reason i really get flash and i mean the only reason is so i can flash from behind a wall into an opponent and catch them of guard usually giving me a kill. Flash isn't that good at getting away unless from one side of a wall to another and even then because most people run with flash they will just follow you.

Flash will most likely remain the most used summoner spell because of the wide range of plays that can be made. You have the get out of gank free, hope a wall, flash back out of a grab or lethal skill shot, jump after someone flashing away to pick up that kill. Plus there are sometimes when you must have a flash like if the enemy team has a jungle Jarvan no flash well the dunk master laughs at you.

Or you can not be a scrub and make offensive plays and get kills with flash.

Well, I'm support bot and whenever the other bot lane doesn't have flash, it's a guaranteed first blood for us. Every single time, unless they get off a good exhaust. But if we have a ganker come around behind, we kill them anyway with our exhaust. If they don't have cleanse, they'll get raped all day and all it will do later on is negate a single CC spell in teamfights, while we have over-wall escapes and the element of surprise and easier buff, dragon and baron steals not to mention better ganks than they can ever get unless you triple tower dive on one person with whatever inferior summoner spell you're using.

I used to hate it, too, when I didn't use it. Back before 30 that is.