I work in Dublin city centre and live just outside. I'd like to echo a lot of what other people have said in that you need to do a bit more research coming to Dublin, in order to find the good stuff to visit. The Guinness Storehouse is the biggest tourist attraction and I have never understood why but reading these posts I now get it - it is obviously heavily promoted by our tourist board but under-enjoyed by the tourists who actually visit it. Similarly with Temple Bar, our tourism industry is not doing the tourists any favours by promoting it as it seems that they don't actually enjoy it. Totally understand why it's unpopular for the most part - though Temple Bar has great galleries Temple Gallery and Studios, The Gallery of Photography, The Ark Children's Cultural Centre, The Project Arts Centre and The Photographic Archive (think that's the name). It also has an independent cinema - The Irish Film Institute - which has a great programme and a really nice bar (food not wonderful). Temple Bar also has some great second-hand clothes shops for women - check out two different shops of the same local chain - Siopa Eile. A little further into Temple Bar and you come to Scarlett Row which has a few boutiques with Irish designers, an independent bookshop, and some nice cafes. On Saturday in Temple Bar there is also a good food market in Meeting House Square, where you can get the best coffees, hot samosas and delicious fresh oysters.
It's strange that no one has really mentioned the art galleries and museums - The Irish Museum of Modern Art is free (like all galleries) and not only has a great exhibition programme but also has the most beautiful formal gardens. It is also REALLY close to Kilmainham Gaol. Collins Barracks 'The Museum of Decorative Arts and History' is also very close by and all three are pretty much accessible on the Luas line. Over on the north side of the city is The Hugh Lane Gallery which is excellent and shows modern and contemporary artworks, and so has something for everyone with any interest in art. All of these galleries also have talks, events and workshops for alls ages which are often free or cheaply priced, and can be discovered with just a bit of research.
Yes, food can be over-priced, especially right in the city centre. But because Dublin is so small you can get to better places in quite a short time - check out places on Camden Street area such as The Cake Cafe (day time only), The Lucky Tortoise (20 bucks for a platter of small dishes) and Simon's Place for old-school sambos. Steer clear of The Market Bar - the food is terrible. Brother Hubbard's is a great day-time place too - there's one on the south side and another on the north side. The Westbury Bar (quite fancy) is supposed to be great for cocktails. Over on the north side, Parnell Street has lots of Asian restaurants and two of the best are The Hophouse (Korean) and Pho Viet (Vietnamese). Have a drink in the very cool Ballroom of Romance bar afterwards. The Cobblestone pub is a tram ride away from here and is supposed to have the best Irish trad music sessions (haven't been in years).
One other thing to consider, people may be comparing Dublin to other city destinations such as Paris, Vienna, Berlin, Amsterdam, Lisbon etc. But please bear in mind that these cities were capitals of colonial empires - they had vast (ill begotten) resources with which to build the beautiful historic architecture that very much influence the character of these cities and the pleasure they provide as places to wander through. Dublin does not have that history, and does not have that grandiosity.
One final point. Yes, there are a lot of homeless people in Dublin and yes a lot of them have addiction and mental health issues. However, I have worked and sometimes lived in Dublin city most of my life (as have my friends) and have NEVER been attacked by a homeless person, and to my knowledge neither have any of my friends. Just because people are poor and begging does not mean they are dangerous. Of course, it's upsetting to see these people in such desperate circumstances but having them unwelcome on our streets because they make tourists uncomfortable is something that could emerge from tourists repeatedly complaining about the homeless, so please be mindful of this when you make these comments.