Tax paying patterns of Indians

I am not sure if this is only Indians or others too follow this.

At the start of the year when I had to submit my tax plan to the accounts team, I said I'll invest the maximum amount possible and submitted my plan. Now at the end the year, I haven't met that plan. As a result I am having to pay huge amounts of tax in the last few months just before the closing of the financial year. This is a huge pinch on my monthly financial commitments. While I was doing this some of close friends disclosed even they are having to pay big tax. I just did a bit of probing and figured 98% of my friends are undergoing this same pattern. Very few people have met their financial goal that they set for themselves 9-10 months earlier.

I wonder what's wrong with us? All of us are well educated and do enormous amount of planning in our projects and we even succeed in that planning. Still being employed is a proof that success. But when it comes to our own planning why are we failing so miserably?