The point about penance is it should make us reflect on the mercy of God, who forgives us by His grace, not by our good works, because He still loves us. It shouldn’t make us hate ourselves, but should focus our eyes on Him.
A lot of people would like to be given harsh penances, wearing hair shirts, fasting, etc. but that’s a misunderstanding. It’s also dangerously close to believing that we are able to pay for the eternal consequences of our own sins, which none of us can!
The way someone once explained it to me, the old penitential manuals priests used in the medieval Church used equivalents in days’ ‘fasting’ as the way to measure penances, because this was like the minimum currency of the Church. Going without food doesn’t do a lot of good in itself, so it’s the least powerful way of making spiritual progress. For example, the simplest prayer, crossing yourself and saying “In the name of the Father, and of the Son, and of the Holy Spirit. Amen” carried an indulgence equivalent to 7 years’ fasting!
Prayer, almsgiving, scripture reading, or nearly any other positive good work will always be worth more as penance than fasting and self-denial.
Perhaps it’s worth noting that if your priest gives you 1 Our Father as penance, in the old penitentials that was considered the equivalent to 15 years’ (or is it 10 years?) fasting! It’s not that we’re being let off easy, just that what is impossible for man is possible for God.