Can anybody tell me what the rush is all the time to retract the gear ?
This annoys the heck out of me too. I've seen it on the line way too many times. Trigger happy PMs (in both seats), who are more concerned about going through the song/dance than looking for the real cues. Training for positive rate/climb identification is based on teaching pilots to recognise a positive V/S trend and increasing RA. You can both of those parameters (momentarily) without engine power. The FMA for a go around and dealing with the lack of it is way more important than raising the landing gear.