Why did Tupac diss Dr. Dre many times?
When Pac joined the Deathrow the relationship between Dre & Suge was already not at it peak, Suge started to bring his homies (who happened to be members of Blood Piru) to the studio, and a lot of distraction was happening, including violence, two of Dr.Dre friends & members of his past crew were threatened by Suge with a gun and there’s a rumor he made them drink piss because they used the phone in the studio while waiting for Dr.Dre! they will later call the cops.*
Dr.Dre like quiet environment where he wanted to be creative, he is a real Dr when to come to music, apparently he wasn’t happy anymore and felt Suge didn’t respect their agreement so he left him label (Suge handle business he handle music), and even tho he left his part of the studio which is worth Millions of Dollars to Suge, Suge was feeling angry and betrayed, and Pac sided with Suge since he was loyal to Suge Knight & Deathrow so he started dissing Dr.Dre.
Following this, Dr.Dre was not working hard anymore at the last days of Deathrow, barely showing up and being lazy, which was the same time Pac was working on his album out of jail and full of energy, so he accused him of being lazy and not care.
It seems “California Love” (their best & only collaboration) was supposed to be on Dre album, but Suge decided to gave to Pac, because he was pushing his album at the time “All eyes on me”, Dr.Dre was not happy & secretly jealous of the song a huge success.
When Dr.Dre left he took all the masterpieces & productions with him, without even telling it to Aftermath, Suge was so angry & then Pac decided to diss him on a song with the same beat of the song “No Diggity” it’s called “Toss it up”.
Dr.Dre was supposed to be on trial to witness for Snoop Dogg murder case, but he simply didn’t show up, saying he was busy, Snoop Dogg was not so happy about that, and Pac sided with Snoop.
There’s the rumor that Dr.Dre was gay, and used to take transexual home, this rumor was never proven, and it’s obviously coming from Suge, and whether it’s true or not Pac was not happy about it as it ruins Deathrow Gangsta reputation