A few simple thoughts for 17 Tamuz and the start of bein hametzarim:
1) Maharal writes (beg. of Netzach Yisrael) that galus is an unnatural state; it's like a rubber band stretched to its limits waiting to spring back to its normal shape. The Jewish people were meant to live in Eretz Yisrael according to Torah law -- not in Boro Park, not in the 5 Towns, not in Baltimore, Los Angeles, or Melbourne either. It's wonderful to live in a neighborhood with seven kosher pizza stores (I wish I were exaggerating) and other kosher amenities, but those niceties tend to make us forget that this is just our temporary home until we merit to make aliya to Eretz Yisrael.
2) The list of 5 things which occurred on 17 Tamuz listed in the Mishna in Ta'anis are not recorded for historical trivia. On a public ta'anis one should focus on identifying with the historical plight of the Jewish people and the tragedies suffered. Simply skipping a few meals without an awareness of why one is fasting is a lack in the kiyum mitzvah.
3) Zecharya haNavi tells us that in the future the fasts will be transformed into days of Yom Tov. The Shem m'Shmuel connects this idea to the Maharal's explanation of why chol hamoed is a partial Yom Tov: since the days of chol hamoed are sandwiched between days of kedusha, they take on the characteristics of kedusha. So too in the future, these days of mourning will be sandwiched historically between our election as Hashem's people and our complete redemption and at that point they will become holidays. The lesson here is that history read forward is incomplete. Sometimes it is only in retrospect that we appreciate events or change our interpretation of them. With the coming of mashiach will we have the perspective necessary to see how even these days of tragedy contain simcha, but until then we must patiently wait with bitachon.