People who are in pain, have lost control of their lives, have been wronged or have been lied to tend to get angry very easily. This is true regardless of age. However, it is also true that older adults tend to get angry a lot. And, sometimes, regret is a huge part of why some older people are always grumpy because they wish they had done things differently when they were younger. Also, some elderly have less ability to function in noisy and confusing environments and thus too much stimulation can cause stress as well as anger.
As an older adult and as a Christian, the only way you can keep your calm is by embracing God’s word.
From James 1:19-20
This you know, my beloved brethren. But everyone must be quick to hear, slow to speak and slow to anger; for the anger of man does not achieve the righteousness of God.
From Romans 12:17-21
Repay no one evil for evil, but give thought to do what is honorable in the sight of all. If possible, so far as it depends on you, live peaceably with all. Beloved, never avenge yourselves, but leave it to the wrath of God, for it is written, “Vengeance is mine, I will repay, says the Lord.” To the contrary, “if your enemy is hungry, feed him; if he is thirsty, give him something to drink; for by so doing you will heap burning coals on his head.” Do not be overcome by evil, but overcome evil with good.
From Ephesians 4:26-31
26 “In your anger do not sin” : Do not let the sun go down while you are still angry,
27 and do not give the devil a foothold. 28 Anyone who has been stealing must steal no longer, but must work, doing something useful with their own hands, that they may have something to share with those in need. 29 Do not let any unwholesome talk come out of your mouths, but only what is helpful for building others up according to their needs, that it may benefit those who listen. 30 And do not grieve the Holy Spirit of God, with whom you were sealed for the day of redemption. 31 Get rid of all bitterness, rage and anger, brawling and slander, along with every form of malice.
From Colossians 3:5-10
5 Put to death, therefore, whatever belongs to your earthly nature: sexual immorality, impurity, lust, evil desires and greed, which is idolatry. 6 Because of these, the wrath of God is coming.[a] 7 You used to walk in these ways, in the life you once lived. 8 But now you must also rid yourselves of all such things as these: anger, rage, malice, slander, and filthy language from your lips. 9 Do not lie to each other, since you have taken off your old self with its practices 10 and have put on the new self, which is being renewed in knowledge in the image of its Creator.
From Galatians 5:16-26
16 So I say, walk by the Spirit, and you will not gratify the desires of the flesh. 17 For the flesh desires what is contrary to the Spirit, and the Spirit what is contrary to the flesh. They are in conflict with each other, so that you are not to do whatever[a] you want. 18 But if you are led by the Spirit, you are not under the law. 19 The acts of the flesh are obvious: sexual immorality, impurity and debauchery; 20 idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions 21 and envy; drunkenness, orgies, and the like. I warn you, as I did before, that those who live like this will not inherit the kingdom of God. 22 But the fruit of the Spirit is love, joy, peace, forbearance, kindness, goodness, faithfulness, 23 gentleness and self-control.