We may not be the best economy in the world, and we may even look like we didn't perform to our potential when viewed with a purely economic lens, but I'd like to point out some impressive and strangely inadequately appreciated achievements.
Please be advised that this is an ad-hoc list from the memory of one Indian, but feel free to add yours in comments.
The perfect must not become the enemy of the good.
Ensuring food security for her people - with no famines since independence. The Indian population has tripled, and food-grain production more than quadrupled. Gone are the days of tragically regular famines under the British. Green revolution, and operation flood were unparalleled victories in the history of the world. India is an exporter of food and is the world's largest milk producer,
Uplifting backward classes without a bloody revolution like in China or Russia. The social inequality in India in 1947 was very likely worse than in any other nation of the time, and yet where China and Russia sacrificed millions and placed their populace under oppressive regimes in trying to achieve class parity, we strode on the path of democracy and freedom. Our track record isn't harmonious or perfect, but what we have achieved with the least amount of blood shed is impressive.
Universal suffrage was enshrined in the constitution before it was popular, 70 years of free elections, the only large democracy in the region (from Israel to Japan) with a track record of stability - even IG, who was the largest threat to democracy dissolved her emergency regime and held elections.
Achieving success in high technology ventures such as IT, space, medicine, education and pharmaceuticals without letting the crushing poverty stop us, or allowing major powers to bully us into buying everything from them. We are a medical tourism destination, a software and ITES success, a generic pharma leader, a low cost space operator with remarkable success, and one of the largest providers of higher education.
Having a stable currency and financial system without a financial melt down like Indonesia or Korea; not going bankrupt despite the massive capital outlays that were required to start several heavy industries, and having a reserve bank that weathered several major world financial crises while remaining transparent and not resorting to secretive currency manipulation or otherwise manipulating world markets. This is remarkable when the "exemplar" western economies have time and again meddled with the scale - whether it be fixing LIBOR, using multi-lateral banks as a hidden lever in negotiations, drafting the WTO and other agreements to exclusively help them, and stalling India with sanctions and trade barriers.