* In the season two episode "Bounty" of ''Series/NCISLosAngeles'', Deeks and Kensi are shown to have trouble trusting each other, with most of the problems originating with Deeks. Reasons aren't given, but it can be assumed that it might be because Deeks still feels new and isn't sure of where he fits in... and then you remember that his last partner, Detective Traynor (season 2 premiere), who he was also romantically involved with, was killed by an explosion. He's got trust issues because his last partner died horribly and he doesn't want to get too friendly with his new partner in case the same thing happens to her.
* In season 3's The Debt, Deeks' position is disbanded and he is forced to return to LAPD. When he leaves Kensi seems to be on the verge of confessing to having feelings for him, but he gets awkward and gives her a half-hearted goodbye instead. This makes sense later in the episode when [[spoiler: he is revealed to have gone back to investigate LAPD's taskforce and was never out of NCIS, meaning he stopped Kensi saying anything so that it wouldn't affect their partnership later]]