Thank you. I just wanted to know if everything is OK.

Which sentence should I include (4 or 5)?

1) At the end of the lessons we walked in (??) Dublin and also visited some museums.
2) On weekends we made excursions.
3) On a Saturday we went to Kilkenny, a medieval city and saw its sights. I also played rugby.
4) I like all of this holiday except the food because the Irish use a lot of butter and they don't eat bread or pizza.
5) I really had a good time on holiday. The only thing I didn't like about my holiday was the food because Irish people use too much butter and don't eat pizza or pasta as we do.

Commas needed in 1, 2, and 3.

http://grammar.ccc.commnet.edu/grammar/commas.htm

Use 5 rather than 4.

Both sentence 4 and sentence 5 could work, depending on the context and the tone you are trying to convey.

Sentence 4: "I like all of this holiday except the food because the Irish use a lot of butter and they don't eat bread or pizza."

This sentence is more concise and direct. It focuses solely on your dislike of the food during your holiday. It doesn't mention your overall enjoyment of the trip.

Sentence 5: "I really had a good time on holiday. The only thing I didn't like about my holiday was the food because Irish people use too much butter and don't eat pizza or pasta as we do."

This sentence provides more context and explains that you had a good time overall, but your dislike of the food was the only negative aspect. It also compares the Irish food to what you are accustomed to eating.

Ultimately, the choice between these two sentences depends on how much detail you want to provide and how important it is to mention your overall enjoyment of the holiday.