This Pitra Paksh, propitiate Your Ancestors

अश्राद्धे कुपिताः पितरः संनिपत्य स्वबन्धून् विनाशयन्ति। अश्राद्धे कुपिताः पितरः संनिपत्य स्वबन्धून् विनाशयन्ति। (Garuda Purana, Preta Khanda)

When rituals like Tarpan and Shraddha are not performed, the ancestors become highly displeased. They return to their descendants' homes and inadvertently cause destruction, delays, and obstacles in their family lineage.

Conversely, when satisfied, they bless their descendants with generational prosperity, longevity, and ultimate liberation. 

नमस्येऽहं पितॄन् मर्त्यैरर्च्यन्ते भुवि ये सदा।श्राद्धेषु श्रद्धयाभीष्टलोकपुष्टिप्रदायिनः॥ (Garuda Purana, Ruchi-krta Pitru Stotram)

I salute those ancestors who are continuously worshipped on Earth by mortals. When offered water and food with deep faith (Shraddha), they grant the fulfillment of all worldly desires and nourish the growth of the entire family lineage.

You can make your pitris after-life transition easier through offerings of water (tarpan) and food (pinda) made to beings entitled to act as mediums during this time, through i.e. Panch Bali to cows, dogs, crows, gods, and ants/insects.

गोभ्यो श्वभ्यश्च काकेभ्यो देवेभ्यश्च पिपीलिकाः । अन्नं संविभजेत् प्राज्ञः पञ्चबलिं प्रकल्पयेत् ॥ Garud Puran: Acara Khanda (First Section), Chapter 20

A wise person must split and distribute food (annaṃ saṃvibhajet) into five distinct sacrificial portions (Pancha Bali), specifically setting them aside for: the cows (gobhyo), the dogs (śvabhyaśca), the crows (kākebhyo), the demigods/devas (devebhyaśca), and the ants/insects (pipīlikāḥ).