I dropped this at chapter 44. I've been trying to hold on since very early on, hoping it will get better, but I just can't anymore.
The MC is mentally 30+ years old already, but he behaves worse than his current age (4-7 years old). What broke the straw for me was when he started a fistfight with another 7-year-old kid (not his first time) because of a minor disagreement over food DURING a noble party. It was truly appalling, especially considering he is able to handle abuse (both physical and mental) from his father, mother, sister, maids, and many others. He blurts out words without thinking, and this kind of HARDCORE uncouth behavior will ruin his job and social life in this day and age, or anywhere really. He acts without thinking, playing childish pranks on others. He has knowledge of his previous life and is also a genius at magic but only gets to use them for his inventions, playing around, and doing pranks. He wants to have a slow life, but it looks like he enjoy being abused instead. Everybody walks all over the MC, and he just tolerates them. But when it matters most, like not starting a fight with a child at a noble party, the MC somehow snaps into the most childish behavior ever.
The worst part is: many side characters are abusive toward the MC. His father physically and mentally abuses him. His mother also physically and mentally abuses him. His sister physically and mentally abuses him HARD, slapping him in the face with a slipper, punching him for no reason, saying 'the voice in my head told me to.' The maids abuse him mentally. Many villagers have no respect for the MC, even as a noble's child, and they abuse him as well. For example, the restaurant owner forces the MC to clean the dishes because he pissed her off by a harmless joke.
99% of the characters treat the MC like trash, and everybody has 0 common sense.
Shoulda rename this manga name to 'Tensei Shite Inaka De Abused Life Wo Okuritai'
Terrible.