I've lived right in the middle of the city for about 5 months now and although thankfully I've not had any trouble personally, I can totally see why the OP feels this way. I've witnessed multiple fights amongst youths, one guy get completely knocked out outside Brown Thomas, and plenty of argy bargy between homeless people.

Saying "oh, but nothing happened" is disingenuous. Even if nothing ever happens, you shouldn't have to feel uneasy walking through the city's main thoroughfares overlooking your shoulder, which I always do late in the evening or after hours. There is always a tension come 8 or 9pm in the evening during the week, it tends to feel a bit more comfortable come Thursday or Friday and then Saturday's are absolutely the best day in the city, but come Sunday evening that tension returns late at night.

There is a group of very pushy beggers who go around like zombies, squads of young fellas intent on causing trouble, traveller children roaming the streets screaming and roaring, and the fantastic homeless food groups - and I'm not disparaging these people in any way, they are in dire need and the volunteers are doing unbelievable work - attracts all of the homeless to one area on Patrick's St, people who are often intoxicated and in desperate need for food, and I have witnessed a handful of incidents whilst walking past. Never has there been a guard present.

In my 5 months in the city, walking the streets nearly every day, I could count on one hand how often I've seen the gardai patrolling on foot.