Its not about listening mate. Any water sharing agreement needs to be fair to both parties. Just cause we are the upper riparian country doesn't make us less "eligible" for the river.
Water sharing agreement is usually based on the command area of a river. Command area is the area around a water system which benefits from the system.
What Bangladesh did was, it made Teesta Barrage I at Lalmonirhat, and increased the command area of Teesta river by over 5 times, to around 150,000 hectares, thanks to the artificial irrigation canal system. The command area would have further increased, by another 100,000 hectares when Teesta Barrage II project would have come online.
Now the problem is, Bangladesh wants India to give her water based on this artificially enhanced(using irrigation canal) command area. So basically Bangladesh will keep making barrages and spreading its irrigation canals and keep increasing its command area and India should just sit there and keep giving them water.
Does this seem fair to you?