The most common and most likely answer to this crossword clue is the 3 letter word YUM
I've seen this crossword clue in The Times
Y
U
M
Buddy explains!

The straight part
We know that "I like it!" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case i like it! = yum.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does YUM mean?
YUM adjective- Delicious.
- Yellowdog Updater, Modified, a popular package manager in Linux
- Indicating delight at the flavor of food.