I believe theres a few definitions for the word "Bad trip"
Theres the kind where your seeing/feeling things that scare you.
Theres the kind where the person may have a (possibly latent)mental illness and they just flip out completely in various ways such as getting violent, delusions, self harm, fear etc and most times when the ordeal is over they dont remember anything and quite often end up in jail or hospital, death is very rare and has never(Well it happened once and the guy shot 300mg by accident, he thought it was coke but 300mg is hundreds, maybe thousands of doses) happened purely due to LSD... so if you experience any of those things regularly with or without drugs then dont do it.
Ive had 2 bad trips but they didnt really fuck me up mentally. Once I got drunk and had 2 1/2 pharoah paper tabs and had a party full of drunk people in my house, this is a bad idea and just something bad waiting to happen being around drunk people on psychedelics. This was back when I thought LSD might be a good party drug, which for me personally its not a party drug unless your at a massive rave or the bush doofs suited to acid trippers. Anyway I got all paranoid and got in a fight with someone really big, he's a good mate though so it was resolved easily. But never the less I still had some amazing moments on that acid after I got everyone out of my house and went with my fellow acid takers on a walk around our diverse suburb, beaches, shops, parks and all kinds of stuff. It wasnt really a bad trip, just bad stuff happened, who knows the same stuff might have happened if we never took the acid and just drank beer.
Then I had a full on mental breakdown not too long ago on a trip that would be close to my 30th on acid not to mention the vast array of other psychedelics I ofted did regularly so it just goes to show you that even experienced trippers can still have a bad trip. I started thinkining id never have a bad trip ever again due to experience of getting out of hairy situations in the past but this just took my mind by storm. I had two friends with me on the same dose(fairly low dose by my standards, 1 1/2 high quality pink panther tabs) they were tripping for their first time on acid thuugh they had tried an array of "tripstacy pills" which are fairly common in Australia so im guessing they had tried at least 2C-B, 2C-I or something of the like but then again it could just be pips, never the less they had some kind of idea of what they were in for and after I left them then saw them the next y they said it was their favourite drugs.
But to the bad part. The trip started like any regular trip does, laughing uncontrollably, mild visuals but we were somewhere else at that point, then we went back to my house and my sister is a very high strung person and very loud which is the opposite of me and can make me quite uncomfortable at times. Anyway we had to get somewhere, my mum was being quite rude and my sister was her regular self and it just made me loose it. It was all in my head and no one could really see the amount of uncomfort I was in, after awhile I could sense my friends becoming uncomfortable coz theres not much to do except wait for our ride to get out of there which seemed to be taking forever but them getting uncomfortable made me feel like it were my fault which made me feel worse obviously. By now the visualls were running wild and my ability to get good visuals is pretty high, I dont understand how people can say they are tripping if theres no visuals??? the visuals were the least of my worries though. To put it quite simply I just felt like I was going truely insane, I couldnt communicate with people, I couldnt think straight and just felt psychologically and emotionally worse than ive ever felt before and thats saying something also. This seemed to all come out of nowhere and like the earlier trip once I got away from everyone and by mysel I felt awesome and it wasnt hard to turn the trip around so I was getting the desired efect from this awesome stuff.
Dont let a bad trip scare you away from acid if your healthy, if you have any mental or psychological problems then id stay away from it. Im riddled with depression and anxiety(though not so much anxiety now coz im on methadone) and im always fine with acid, you just need a very strong mind.
Take it easy brother and if you decide to drop dont go more than one at first and quality is different everywhere so even 1 might be a lot but it shouldnt be too much.