Some points:

1) Treating Pussy as essentially a gopher for years (before he turned informant) despite Pussy being a soldier and having nearly 30 years of service to the Family under Tony and his father. Had Pussy been being paid more he wouldn't have resorted to selling H, which would've meant he would'n't have turned Rat. He could've made a great Capo, much better than Paulie.
2) Not clipping Pussy after Pussy returned. Allowed himself to be blinded by his WISH that Pussy not be a rat, even when he knew in his heart that Pussy was.
3) Treating Richie Aprile with disrespect from the day he got out of the can and taking a civilian (Beansie's) side in that dispute. The enmity which developed between Richie and Tony could've been avoided.
4) Opening the books for Christopher as quickly as he did despite Christopher showing no signs of maturity.
5) Putting Gigi as Capo of the Aprile Crew over Ralpie. In the end, all it did was cause Tony agita and led to Gigi, a loyal soldier, dying a premature death from stress.
6) Killing Ralph over a horse. Ralphie may have been a despicable human being, but he was a Capo and the family's greatest earner ever. Ralph did nothing in terms of the Mob which merited him being killed.
7) Not having Chris clipped when he found out Chris was a Heroin addict. Even Junior told him to basically put Chrissy down, that he was nothing but a liability.
8) Getting Phil Leotardo, an NY Capo, into a car wreck over a money dispute. For one all it did was make Phil hate Tony, two it ended up costing Tony money anyway. He could've called a sitdown.
9) Not giving Tony B. over to NY after he killed Billy Leotardo. It was painful for Tony, yes, but Tony B. sealed his own fate and Tony refusing to give him up nearly caused a war. Him killing Tony B. himself didn't satisfy Phil and laid the seeds for the war that would come. If Tony B. had been given over to NY/Phil promptly, no bad blood between NY and NJ, and Philly might've gotten over it if he had the satisfaction of killing Tony B. himself.
10) Not clipping Chris when he found out Adriana was a rat. Even Chris didn't know how much he told Adriana because of his drugs. This meant that the Feds could've, in theory, used any information Adriana gave them which incriminated Chris, against Chris and might've turned him rat too. As it was, letting a Rat get that close shows Chris had bad judgement.
11) Promoting Chris to Capo JUST AFTER Adriana is killed. I mean Chris fucks up and goes to rehab, than tries to kill Tony, then his fiance turns out to be a rat, all in the space of two years, and he's promoted to Caporegime. Talk about rewarding bad behavior. Now there was no "Buffa' between he and Chris--And what happens if Chris relapses on Heroin and gets cornered by the Feds?
12) Putting Bobby Bacala as being his de facto Underboss.
13) Protecting Vito out of sentimentality despite Vito being gay and New York demanding that he be handed over. Not only was this a repeat of the Tony B. situation, but even members of Tony's family lost respect for Tony due to him "harboring a fa***t."
14) Borrowing money from Hesh, then treating Hesh like shit, which led to the severing of their lifelong friendship and the loss of a valuable unofficial Consigliere.
15) Thinking he could whack a Boss of one of the Five Families, without using any insulation (IE, without having outside people do it to deflect suspicion away from him), without approval, and thinking he could get away with it.

you could say all this kinda of stuff about real bosses....

Some good points there although some of them like him not handing over Vito was largely because he was Tony's best earner and allowed him to get the boat i think he says in one scene. I doubt anyone would like to hand over their best earner.

Same goes for not handing over Tony B other than being his cousin, Tony still felt guilty about lying to him and that he didn't do time whilst Tony B did.

Putting Gigi in as capo was probably done as at that time Ralphie was largely upredictable coke head. Tony killing him because of a horse was the worst though.

I always thought that Tony was a terrible boss - for many of the same reasons detailed above, Crazy Joe. Bottom line was that he was completely selfish and thoughtless to those closest to him. He treated and grieved for animals more compassionately than he did humans. Bottom line on life - it all boils down to how you treat people. It doesn't matter if it is your CEO or the janitor on the first floor of your building. How do you treat people? Horrible person = horrible boss. Deep down, Tony was indeed a horrible person.

I love the Sopranos yet Tony was always my least favorite character I think he is teh most evil guy on the show which says a lot. What i hate most about him s his selfishness and he is vert two faced. In teh first season he tooks abotu how he admires Junior yet he uses junior and basically puts him in jail. Also Tony caused a lot of heartache with new York which was stupid coondiering new york would crush jersey. he was lucky he was friends with Johnny Sack