Someone being toxic is like someone who is actively trying to be horrible to someone, or just plain aggressive for no reason. You tend to find a lot of that on Twitter because the algorithm boosts toxicity and so people are more toxic so they can trend and get a short high from being relevant for 2 seconds and people seeing their tweet. Here on nostr, if someone decides to be toxic they will get muted and unfollowed by a lot of people so it tends to be rare, and tbh my follows list at the moment I have absolutely none. It feels great, Twitter is the type of app you will spend a few hours on each day, at the end of the day you get into bed and reflect on what you accomplished and you will feel like the time was wasted and you didn't learn anything. Nostr is the type of place where I spend say 2.5 hours a day average on it, but I come out at the end of the day with either newly procured knowledge, or at the very least positive interactions which didn't ruin my mood or stress me out.