#3 Vince McMahon
Back in 2015, UFC President Dana White had a Twitter exchange with a WWE fan, which saw him dubbing Vince McMahon's promotion 'fake'. The comments weren't taken lightly by the pro wrestling industry, and Brock Lesnar was one of the guys who didn't like White's comments. According to White, all the WWE Superstars he met were great people, but the presentation was still fake. Brock Lesnar, while speaking with ESPN's SportsCenter, took a major shot at Dana White and praised Vince McMahon in the process.
Lesnar stated that Vince McMahon has better promoting skills than White, and that bothers the latter.
Brock Lesnar bagged success in both WWE and UFC
Brock Lesnar left WWE in 2004 to pursue a career in NFL. When that didn't work out, he went to NJPW and later built a career for himself in UFC. Lesnar became a huge mainstream star in MMA and brought his popularity with him to WWE when he returned in 2012.
Lesnar left Vince McMahon's promotion on a bad note in 2004, but it seems like he is well aware of the pains that a WWE Superstar has to endure, and didn't mince his words while criticizing Dana White for taking a shot at the company.