United were booed off yet again at Old Trafford as they dropped to fourth in the Premier League after their latest poor showing in front of goal.
Marouane Fellaini, Anthony Martial, Jesse Lingard and Bastian Schweinsteiger all squandered good chances to register a much-needed win against West Ham, who were also guilty of wasting clear opportunities.
Boos reverberated around Old Trafford after the final whistle and "attack, attack, attack" could be heard on a few occasions in the second half.
Van Gaal insisted his team were doing most of the attacking, however.
"The fans are disappointed," the United manager said
"I know that because I am also disappointed and so are my players.
"They want to score every minute of the game but it's not possible.
"But I don't understand that they are shouting 'attack, attack, attack' because we are the attacking team and not West Ham.
"It is in every game like that because we are more dominating than our opponent."
Van Gaal defended his tactics, saying his possession-style football had served him well during his successful spells in Spain, Holland and Germany.
"(The booing fans) don't like the style of play from Manchester United, but everyone knows in advance that all the teams of Louis van Gaal is playing like that," he added.
"So when you have that question, then I say, okay, in Barcelona or Bayern Munich or AZ we have played like that."
This was not United's worst display of the season.
Despite having a shot saved by Adrian from three yards, Fellaini provided United with a direct threat in the first half and the Belgian, making his second league start of the season, clipped the bar in the first half with a deflected header.
Martial also caused West Ham problems with his pacy runs and Lingard also proved a threat on the left flank.
However, there was no sharp decision making or ruthlessness inside the box
United, shorn of top scorer Wayne Rooney, lacked a killer finisher and Van Gaal knew it.
"I am pleased with the performance but when you create these kind of chances, you must finish," he said
"That is the most important aspect of football and we didn't do it.
"Otherwise maybe we would already be first in the league after (last weekend's game at) Leicester.
"When you miss chances three metres in front of the goal, yeah, what can you say?"
When asked whether a top striker like Sergio Aguero or Luis Suarez would score goals in is his team, Van Gaal said: "That's a question mark
You never know
I think they would."
West Ham counterpart Slaven Bilic was unable to claim a fourth major scalp on the road, but was happy with his team's performance.
The Hammers boss, who has seen his team beat Manchester City, Arsenal and Liverpool away from home this season, said: "We could have or should have been in front
I think we deserved at half time to be 1-0 up.
"We hit the post twice and had one great chance from Victor Moses.
"It is not very common for West Ham to come here and take something away
It is a good day."
The only disappointment for Bilic was that referee Mark Clattenburg failed to send Schweinsteiger off for what the Croatian deemed to be an elbow on the exceptional Winston Reid.
"It was a moment of madness," Bilic said
"He deserved to be sent off, but the referee told me he didn't see it
Fair enough, I believe it
It was an elbow."
Source : PA
Source: PA