After missing two opportunities, he finally connects on the third. If the explanation is missing, the audience is robbed of the experience and the sequence is robbed of power. This is the part that is more important than Tim getting the date. Getting the date relieves the tension, it is anticlimactic. Building to this point and seeing what influences Tim's decision is the important part.
Characters sometimes do things that are confusing.
To wit, on his quest to gain courage, Tim begins taking a course in pottery. Or Marge, while searching for meaning in her life, slaps a street vendor for asking her for a date. Or Sherry, while trying to help her Uncle recover from a debilitating illness, cuts off her beautiful long hair. None of these actions connect with their storylines. When the character does them, the audience is confused.