Gratefulness can be increased first by understanding the purpose of creation, the shortness of life and that this life is in reality a test. We must know that Jennah is something that must be worked for and earned. Allah says,
"Do men think that they will be left alone on saying, "We believe", and that they will not be tested? We did test those before them, and Allah will certainly know those who are true from those who are false." (29:2-3)
We are willing to sacrifice for work, for earning wealth and for our boss. We become frustrated, worried and stressed when wake up late for work or arrive late on the job. How worried, frustrated and stressed are we when we miss the congregational prayer? Or, when we pray late? Let us inshaAllah reflect on to whom our sacrifices should be made for.
When we complain, let us complain to Allah, not about Allah. Do not assume you'll enter Jennah so easily, look to the stories Allah presents for us of the past; of their hardships and trials. Be patient. Allah says,
"Be sure we shall test you" (2:155)
and, Allah says,
"O ye who believe! seek help with patient perseverance and prayer; for Allah is with those who patiently persevere." (2:153)
May Allah guide us to the truth and give us stability upon it.