I'm gonna choose to get passed of the obvious answer everyone else gives (quick title shot). I also can't explain why everybody else doesn't like him, but I'll tell you why I don't like him.
Brock lesnar uses his size and strength. He's figured out that he's a big dude and that if he does everything quick along with using ONLY his size and strength, he could win.
Brock is a good wrestler. I'll admit. Yet, he is not anything special. He only uses his size and strength THAT'S IT. Beyond that he hasn't proven to do anything passed be a big guy.
I get annoyed when I see great fighters such as Carwin and Velazquez with the records that they've got not get their title shot and not even get the recognition they deserve. Just watch what Velazquez did to cheik and Carwin do to Gabriel Gonzaga. (Can't wait to see Carwin tear up some other guys).
Brock's record is like this:
1.) Finished his first fight in Pride against a guy who's lost more times than he won. YAY.
2.) Lost to Frank Mir a future hall of famer.
3.) Couldn't finish Heath Herring, a mediocre fighter.
4.) Finally beats Randy Couture. Couture seemed to be doing VERY well against Lesnar. Lesnar drops him and quickly Couture gets up (which shows how effective Lesnar is against a very good wrestler). Lesnar knocks one lucky punch against Couture and Lesnar wins. Give Couture a rematch and Couture will take his belt back because Couture is a smart fighter and a very good fighter.
Another reason I don't like Lesnar, is that he has such an incredible ego. He was like "That old man had the guts to face a young buck like me..." ya, and that old man lost by the mere chance that he got caught. It showed no talent to actually punch someone with big fists (like I said, he uses his size to his advantage: which is smart, but shows how weak his wrestling is). He also laughs at Heath Herring. He needs to get an *** beating, and he needs to fight better quality fighters. Let's see how he does with Nogeira, Carwin (who I think will play with Lesnar and use him like a chew toy), Velazquez and Mir. If Brock has the guts to face Fedor (In which he for a one time only fight goes to pride or fedor to UFC or some way there is some match up) Fedor will make Brock look like a trainwreck.
When Brock was asked about fedor Brock got very defensive and started getting very irrate (just like a young, amateur, inexperienced, self conscious fighter would act). When Fedor was asked about Brock he calmly said that he would like to fight him and was answered very amicably.
I'll summarize for those who didn't wanna read my rant.
1.) Egotistical
2.) inexperienced
3.) Unproven