Dave Mustaine talked about all the lineup changes MEGADETH went through over the years, saying how it wasn’t easy to march on every time. He told Jamey Jasta (as transcribed by Ultimate-Guitar.com):

“It’s no fun having to replace musicians. It’s hard because, along with having to replace the person and the band, you usually end up having the personality loss. And very rarely do guys leave on good terms.

“Marty [Friedman] had a nervous breakdown and he quit. And I remember, it was like ‘Did I do this?’ And [David] Ellefson has told me after the fact everything that was going on with Marty before that happened, so I’m very happy to know it wasn’t me.

“And a lot of the other guys when you have to let them go – you know, it’s really hard to fire somebody and remain friends with them.

“Unfortunately we had to let some guys go. It’s not because I don’t love them and it’s not because they’re not good. It’s because what our vision was was not a common goal anymore.

“I mean there were a couple of situations where one guy called up my fiancee and said ‘I fantasize about being with you when I’m with my girlfriend.’ And I thought ‘Oh, you’re fired.'”

Asked if he’d ever do a hip-hop collaboration, Dave replied:

“I would never do that with Megadeth. I wouldn’t mind playing on somebody else’s record, but Megadeth has been kept pure for a reason. And we’re not gonna do a ‘Lulu,’ we’re not gonna do a mash-up, we’re not gonna do anything like that. We’re gonna go on experimentation with the four of us.”

During the rest of the chat, Mustaine explained why he never found it appealing to be a session musician, saying:

“Every time you go into a studio you can learn something if you’re paying attention and you wanna learn something.

“I know guys that are going to the studio and are session players. They go in, they punch the time clock, and they leave. And it’s just like cartoons with the wolf and the sheep, ‘Hello Sam! Hey George!’ Day’s over and they leave.

“For me – I couldn’t be a session guy. I think that it would be so vanilla pudding that I would hate doing it. I like to create, to do my own thing. And that’s why when you talk about different styles of music that’s a part of who I am.

“When I wrote ‘The Blackest Crow‘ [off 2013’s ‘Super Collider‘] people didn’t like that song. I don’t give a f**k, it’s about my mother-in-law dying from Alzheimers. That’s what I felt 0 it felt like the blackest crows in the world were in my house, everywhere I went. It was awful. [Watching somebody die from Alzheimer’s] is like watching ice sculpture melt before you.”