Anything can be good for you if you want it to be.
That sounds like a fairy statement straight out of some self-help book, so let me explain.
Sustainability is the most important part of any diet.
The 'stickability' of a diet will determine it's success more than the actual food it contains, as long as it adheres to suitable calorie targets. Someone who sticks to a 'pretty good' diet for a year will have much better results than a person who sticks to a strictly 'clean' diet for two months.
Which leads me to my next point.
There are no good or bad foods. Sure, there are foods that are 'better' for you and foods that 'aren't as good'. But think about it this way.
Don't aim for perfect, all of the time. Aim for pretty good, most of the time.
You already know that your 'healthy' diet should consist of meat, fish, eggs, fruit, vegetables, complex starches, nuts and seeds. That's pretty boring though, right? Where's the tasty stuff? I like to think of it as all of this food making up most of my diet (let's say around 80%) with a little wiggle room for food that definitely doesn't make the 'healthy' cut.
So, what does this mean?
It's all about moderation.
Eat everything in moderation. Nobody got fat from eating one pizza and nobody got shredded from eating one salad. What matters more is what you eat over a long period of time (I'm talking years). As long as your diet is 'pretty good', you will see results.
If eating that pizza controls your hunger cravings and stops you binging on food for a week then that pizza is psychologically good for you. It should be part of your diet.
Find which of the classical 'bad' foods that you find most satisfying and implement them, in moderation, into your diet. For me, it's definitely ice cream. Every few days I let myself have some ice-cream guilt free because it's part of my diet and I know if I forbid it I'll hate life and go off rails.
In this case, ice cream is good for me.
P.S. Remember, calories still matter in any diet. 'Bad' food is often called bad because it's high in calories and can easily push you into a calorie surplus and cause weight gain. Ensure you're eating at your maintenance calorie level if you want to maintain your weight, or below it, if the goal is weight loss.