I've met upwards of 50 UFC, WEC, and Strikeforce fighters since 2006. Just wanted to share some insight on who is really cool and who isn't the most fun to meet.
Nicest :
Pat Barry - Super down to earth and a big kid.
Heath Herring- was eating at hooters the night before his fight with Brock. Took pictures and signed for everyone.
Jon Fitch- Met him twice. Once before his fight with GSP and once again in Vegas. Nice guy.
Ben Rothwell - Met him at Strikeforce Hendo vs. Fedor. Took pictures with everyone that asked.
Meanest :
Phil Baroni- met him in Vegas at UFC 98 or 114, I can't remember which. Very arrogant and unpleasant to fans.
Matt Hughes -met him on 3 or more occasions. He was equally insufferable each time.
Brock - no surprise here but not very friendly.
Tiki ghosn- he was hanging out with rampage on UFC 87 fight weekend. Was basically Rampage's sidekick and not half as funny or entertaining.
Feel free to add your own meetings and experiences. 
gerald harris.. nice guy
ill sa
It's odd but everyone I know who met Sam Stout said he was a complete douche.
Nicest: Tank, Fitch
Asshole: Ken Shammy
Thumbs up- Wanderlei, Ellenberger, Shields, Maynard, Belcher
Thumbs down- Guida
clay guida said I was doing a good job and keep training.
donald cowboy cerrone said his sister has the same pants as me lol.
Also have you guys seen that video where Baroni makes fun of some fat kid lol
Urijah faber= super cool guy.
epic hero - It's odd but everyone I know who met Sam Stout said he was a complete douche.He was good when I met him at UFC 83 in Montreal.
Back in the cable dark days, I used to drop off publicity posters for the UFC at AKA in San Jose. One time, my six year old son went with me. He was pretty intimidated by the whole scene, but one guy saw him and said, " Hey, what's up, little man? You gonna come in here and show us how it's done?"
My boy lit up, thinking he was being shown some respect by one of these HUGE guys.
That was Mike Kyle who treated my son like a man.
A couple off the top of my head are Eugene Jackson (old schooler) was cool as fuck in all my interactions with him. Bob Sapp (he used to be a fighter...) is one of the funniest dudes I've ever met.
Leghound, I met Eugene at a Prince concert. Yes, cool as hell.
For sure! He used to roll with us quite a bit at Fairtex. One of the nicest guys I've met, fighter or non-, and to me that's the mark of a true man - none of that wannabe tough guy fake mean mugging bullshit that the kiddies here get off on
Rich Franklin and Junior are the 2 that stand out in my memory as the nicest.
haven't come across a mean fighter yet.
Josh Barnett, Don Frye, and Eddie Bravo were all cool as fuck when I met them at Strikeforce. And I didn't meet Donald Cerrone at the show, but he seemed to go above and beyond...I saw him take pics with over 25 people while very much enjoying himself.
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Fabricio werdum and Bigfoot silva were both cool as hell. They stood around and madea genuine effort to sign as much stuff for people as possible and always were really friendly and approachable. Got the sense that Fabricio was really enjoying the fans. Shot the shit with Brett Rogers for about 20 minutes and he was really down to earth and funny as hell.
Meanest was easily Valentijn Overeem. Brushed people off and acted like someone had shit in his cornflakes by asking for an autograph.
Before UFC 126, I went shopping at the outlets and seen Machida and his possee hanging outside. My friends and I recognized him, and whisper like little gay fanboys from a distances. I guessed he noticed us and calls us over in his broken english. Had a chance to chat and take some pics with him. Super super respectful nice guy, but honestly I really couldn't understand most of what he was saying, but it didn't matter, made my day.
ThirdJackson - Thumbs up- Wanderlei, Ellenberger, Shields, Maynard, BelcherWhat's your guida story
Thumbs down- Guida