i don't believe they affect your personality no, that's not what it does or is for. Horoscopes are predictions on how you may feel depending on where the planets are aligned around the sun
they are also set up to mislead people who havent studied astrology. If you're reading a horoscope by your sun sign it will be wrong or really vague since they base them off of your first house or "rising/ascendent/" sign. I never really could tell for a while but I spent two years learning and tracking the predictions. its pretty on about 85% of the time, you just have to know what you're reading. what made me learn about it was sometimes id read horoscopes and it would say something like, "in your third house of.." and id wonder how it knew what house whatever was in and I didn't even know
in astrology every person has three signs. a rising, sun and moon
rising sign=outer self and how others see you
sun= your true personality
moon=your subconscious personality
then depending on when and where you were born you have 10 houses that make up the aspects of your personality based on the where they fall on the chart that range from, how you communicate, one on one relationships, love life, what kind of parent you are or will be, etc. for ex: your sun/moon/rising signs also fall into a specific house based on where the planets where when you were born that go even deeper in explaining yourself. thats why usually when people just read a general zodiac profile description, its part on and off. so if you base your judgement on, I was born so and so, so I'm a _______. you'll only get a little piece of the picture
of course a lot of religious people think its demonic. i just kind of see it as like a tip or life hint, the older i get and learn more about myself, the more right it seems. it also makes sense to me that the other planets revolving around the sun energy would affect us in earth, i mean you can see it by how the moon affects water, which we're 90% of. also not trying to persuade anyone, just my opinion on it