Latvian Gulbis is widely regarded one of tennis' biggest unfulfilled talents, and he is also a player who loves to be outspoken.
So it was not a surprise that it was the 24-year-old who voiced such views in an interview with French paper L'Equipe ahead of his second-round defeat by Gael Monfils at Roland Garros.
Gulbis said: "The current tennis is sorely lacking in character. I respect Roger, Rafa (Nadal), Novak (Djokovic) and Murray, but, for me, all four players are boring. Their interviews are boring. Honestly, they are boring."
Murray pulled out of the French Open last week because of a back injury but, in an interview with GQ out, the world number two admitted he deliberately makes his press conferences boring to avoid controversy.
The Scot experienced the other side early in his career on a couple of occasions when comments he made became a big story, and he said: "As an athlete, all I do is try my best to be as good as I can be as a tennis player.
"Whether people like you or not should be irrelevant. But, to be honest, over the years I have found it difficult to open up and be a bundle of laughs in press conferences or interviews.
"I always try to give honest answers, but they are fairly boring so I don't have to deal with the aftermath of any scandals.
"I would say that I am different from what a lot of people think I am like. What would bother me is if the people around me started telling me that I had begun changing, being an arse, or something. That's when you take it seriously.
"You don't get to see what people are really like from in front of the TV. It is very easy to be false and fake in front of the camera.
"But to tell jokes and be fun all the time, that's not actually very hard to do. If you are going to be truthful and tell things like they are, that is much harder."
Gulbis singled out Federer for influencing other players, saying: "I often go on YouTube to watch interviews. I quickly stopped watching tennis interviews. It's a joke.
"It was Federer who started this trend. He has a superb image as a perfect Swiss gentleman. I repeat that, I respect Federer, but I don't like the way that young players try to imitate him."
Federer echoed Murray's thoughts, but also believes the number of interviews the top players have to give inevitably makes them less interesting.
Speaking to the Swiss press, he said: "I understand it, our interviews are not always the most exciting. But that's not just our fault, that's the machine. After each match, we have to give press conferences.
"But also you cannot say anything you do not like about something to someone without being totally criticised by many people. Therefore, everyone is very careful.
"On the other hand, I also think it's nice that we treat each other with respect."