A long answer:
Imagine someone gives you a huge plot of land, with enough resources to build a house, houses, gardens, basically everything to sustain, and have a happy life. You work hard, build your house, some houses, you plant gardens and make it a really nice place. Just you feel a bit lonely and isolated, so after some time you decide to invite some other people to live in the territory. Which is nice at the start, but after the people you invited, are having fights with each other, are mistreating the animals, are polluting the garden. You try to make some rules for them, in order to live healthy in peace and happiness, but they ignore those and things are getting worse and worse. Should you force them to listen with violence? What can you do? You keep warning them and mention that listening to your rules would be for their own good. But they react who are you to decide what is good for us, what would make us happy. So you decide to stop your support to them, you do not provide food any more, you stop to take care for their plots of land, in order should bear the consequences of their actions. They start to complain to you and accuse you of behaving as a dictator, trying to force them to live according to your rules. You react that you just want what is best for them, but they are free to do what they want; listening to your rules would make them healthier, happier, and it would show some appreciation for being invited and having the possibility to live in such a wonderful place. They react: what is wonderful about this place; the earth is poisoned, the animals are suffering, the houses are slowly becoming ruined, it is dangerous to go outside because of the violent people. Why should we be thankful to you for living in this miserable place?
This story is just a fictitious brief illustration, but it has many similarities with the situation of mankind and God. God and his heavenly helpers designed the universe and the forces of nature to establish life on earth. And he asked people to expand the paradise garden, giving few principles and rules (Genesis 1-3). But people had freedom of choice decided to do things their own way:
Genesis 6:5,6 Consequently, Jehovah saw that man’s wickedness was great on the earth and that every inclination of the thoughts of his heart was only bad all the time. 6 Jehovah regretted* that he had made men on the earth, and his heart was saddened.
So basically the present world and its suffering are just the consequences of the decisions and actions of people living around us and before us. In the time in between God created several times possibilities to have a sort of "restarts", with Noah (for all of humanity), with Abraham and Mozes (for a specific nation), with Jesus (just for a subset of people who voluntarily want follow his ways). He gave detailed rules (Leviticus), and he gave principles:
Matthew 22:37 He said to him: “‘You must love Jehovah your God with your whole heart
and with your whole soul and with your whole mind.’ 38 This is the
greatest and first commandment. 39 The second, like it, is this: ‘You
must love your neighbor as yourself.’ 40 On these two commandments
the whole Law hangs, and the Prophets.”
But in the end, people only listened locally or temporarily as a collective or (small) subset. The difficulty is that even if individual people try to go by the principles and listen his rules, they are still suffering the consequences of actions of the many other people who are not listening and who are causing suffering, pollution and even persecute those who try to follow Jesus way of life that leads to unity with God's purpuse.
That is why Jesus prayed the following in John 17
17 Jesus spoke these things, and raising his eyes to heaven, he said: “Father, the hour has come. Glorify your son so that your son may glorify you, 2 just as you have given him authority over all flesh, so that he may give everlasting life to all those whom you have given to him. 3 This means everlasting life, their coming to know you, the only true God, and the one whom you sent, Jesus Christ. 4 I have glorified you on the earth, having finished the work you have given me to do. 5 So now, Father, glorify me at your side with the glory that I had alongside you before the world was.
6 “I have made your name manifest* to the men whom you gave me out of the world. They were yours, and you gave them to me, and they have observed your word. 7 Now they have come to know that all the things you gave me are from you; 8 because I have given them the sayings that you gave me, and they have accepted them and have certainly come to know that I came as your representative, and they have believed that you sent me. 9 I make request concerning them; I make request, not concerning the world, but concerning those whom you have given me, because they are yours; 10 and all my things are yours and yours are mine, and I have been glorified among them.
11 “I am no longer in the world, but they are in the world, and I am coming to you. Holy Father, watch over them+ on account of your own name, which you have given me, so that they may be one just as we are one.
So Jesus know that it was going to be hard and difficult to live in a world of suffering. But God send Jesus to tell us a message of "good news" that in the future things will get better, and Jesus asks God to help his followers until that time.
John 5: 28 Do not be amazed at this, for the hour is coming in which all those in the memorial tombs will hear his voice 29 and come out, those who did good things to a resurrection of life, and those who practiced vile things to a resurrection of judgment.
so there will be a resurrection, and
Revelation 11:18 But the nations became wrathful, and your own wrath came, and the appointed time came for the dead to be judged and to reward your slaves the prophets and the holy ones and those fearing your name, the small and the great, and to bring to ruin those ruining the earth.”
So Jesus and God, will clean up the earth, for a good cause:
Revelation 21:3,4 ...The tent of God is with mankind, and he will reside with them, and they will be his people. And God himself will be with them. 4 And he will wipe out every tear from their eyes, and death will be no more, neither will mourning nor outcry nor pain be anymore. The former things have passed away.”
So to summarize a short answer:
Reasons to love God are that he created the earth to be inhabited by people and animals in Harmony, with the intention to establish a Paradise for a society of humans. But humans have a free will, and until now most of them messed it up. However, God still want to pursue his goal, he gives principles to live by that help to even now live a relatively healthy and happy life in a miserable world, moreover, and he promises that one day there will be a resurrection of the death and the intended paradise will be restored.