"Tough Guy / Clean vocals" in modern metal. Usually in some metalcore, melodeath, or even progressive metal nowadays. It almost seems less like alternating the styles to fit a song or make an interesting, dynamic shift, but just because they "have to." It's become so prevalent that it's almost become a requirement to the point that one of them usually ends up being awful. Either you have a song with great growls and weak cleans and or good cleans and really forced growls. Take Trivium for example. Now, I kind like Heafy's cleans, they aren't great, but I think he does well with them, but his growls and "tough guy" vocals are terrible. Either he's doing some weird Hetfield-esque imitation or some sort of pseudo-growls.
Soilwork is another example, although I think Strid is actually good at both approaches, but I think they would be a much more interesting band without the clean, catchy choruses and just go full on with the heavy growls. I'm not sure I could take a full album of Strid's clean vocals though.
The "Beauty and the Beast" vocals that plague oh so many symphonic bands are even worse. Not only do many of those bands sound like bland, carbon copies of each other, but those growls are usually awful. Nightwish does it just fine because Marco doesn't really growl, he just provides more of a counterpoint, I guess, and his vocals aren't that bad.