The most common and most likely answer to this crossword clue is the 7 letter word TURN-ON
I've seen this crossword clue in The Guardian
T
U
R
N
-
O
N
More clues leading to the result TURN-ON
Buddy explains!
The straight part
We know that "reason to get excited" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case reason to get excited = turn-on.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 TURN-ON mean?
TURN-ON noun- Something that attracts, gives pleasure, or encourages, especially sexually.