One thing I am happy doing is making mistakes. Because every failure brings with it a learning (and a very valuable one at that). But even mistakes need 100% effort.
When I killed my first entreprenuerial journey mid-way or when I choose not to become an engineer, the result was a stamp of failure slapped on my face. I am still happy about my decisions because I gave them my best shot. Today, I know what it takes or what the trade-offs are.
Side Note: Since my childhood days, I always knew that if I was getting only 60% marks, it was directly proportionate to my efforts. The balance 40% is always up to us – be it academics or life.